Credit Card Machine Question

July 3, 2006 6:46 PM

Did my typo on the credit card machine double-charge a customer?

At work the other day, I was entering someone's total, and fat-fingered it, entering an extra digit. (The machine is a Tranz 330 or similar.) I realized the mistake right after I hit "Enter" on the machine, but I pressed "Cancel" a fraction of a second later. There's no way the machine was able to dial out and authenticate the card.

It didn't occur to me until later on that that it was possible they'd be charged anyway when we ran a batch at the end of the night. Would they have been charged if I hit "Cancel" before the machine authenticated the card?

posted by fogster to work & money (13 comments total)

I honestly don't know the answer to this, but I know that if they WERE double charged, the customer will be on the phone as soon as they find out about it.

Make a note of the transaction number, so that when they come complaining, you can easily void the problem transaction.

And apologize of course.
posted by misanthropicsarah at 6:58 PM on July 3, 2006

If they were double charged your credit card totals wouldn't have matched the register totals when you closed out.
posted by cali at 7:06 PM on July 3, 2006

The problem is that I'm not a manager, and didn't think at the time to bring it to the attention of one. I don't know if the drawer balanced, and it's even possible that no one has gotten around to asking me about a discrepancy, if one exists, yet. (Besides, it would be in our 'favor.')

I was hoping someone was familiar enough with the workings of the machines to be able to tell me if it would have charged them or not, so I can try to stop worrying.
posted by fogster at 7:12 PM on July 3, 2006

I have done this before (hitting CANCEL) before the terminal handshakes, and no double-charge is made. I have a Linksys terminal. From what I've seen, after working with this terminal zillions of times since 1997, the charge is not made unless an authorization number appears (and even then you can void it anytime before a batch close). Sometimes during the actual connection, hitting cancel has no effect, and you get an authorization.

Of course the only way to verify this is to log into the merchant account and see the statements.
posted by chef_boyardee at 7:15 PM on July 3, 2006

Correction... Linkpoint. I have no idea what the hell a Linksys is.
posted by chef_boyardee at 7:16 PM on July 3, 2006

(Linksys is a company that makes routers, switches, and other networking equipment. You had me wondering when Linksys got into the credit card business.)

Your post is somewhat comforting; my concern was that it'd be stored in the memory and added when we did a batch settlement.

We're largely a paper-based business, so I don't think we have a way of looking online to see if it's there. (The batch would have already been run, so there's nothing I can do to void it at this point either way.)

For that matter, though, are there any safeguards? What stops me from running a card for, say, $2,000 instead of $20?
posted by fogster at 7:22 PM on July 3, 2006

What stops me from running a card for, say, $2,000 instead of $20?

Probably not much beyond your own accounting procedures. I once made a coding error in an online credit card processing application. During its first trial run, My error succeeded in processing nearly twenty two thousand dollars on one poor victim's card instead of a little over three thousand (it got processed seven times). Fortunately the discrepancy was an obvious one and we were able to void the extra transactions, and of course correct the underlying coding error that allowed it to happen in the first place. Not exactly my proudest moment.
posted by Lokheed at 7:33 PM on July 3, 2006

I have seen someone get charged $7000 instead of $70 on their DEBIT card. Needless to say, it was a decent-sized pain in the ass to get it sorted out. I have also seen a bank teller enter a person's account number in the "deposit amount" field, which got them temporarily credited with something over $4,000,000,000. The bank cleared that one up right quick. Be careful entering those financial transactions people.

In your case, I think Chef Boyardee is right. If you don't get an authorization number, the transaction has not been authorized, and has not happened.
posted by Rock Steady at 9:23 PM on July 3, 2006

What stops me from running a card for, say, $2,000 instead of $20?

Do you give your customers receipts? I know if I got a receipt that said $2000 on it, I think I would probably stop you.
posted by SuperNova at 9:49 PM on July 3, 2006

Well, in lots of small businesses the credit-card machinery isn't connected to the receipt machinery. A human types in the charge amount, just like a human counts the cash. (I have no idea how fogster's business is set up, of course.)

I assume you get some sort of periodic (monthly?) list of transactions from the credit card folks, and you could make a note to check that list for a suspicious double-charge on the day this happened, if you want to be sure.
posted by hattifattener at 12:25 AM on July 4, 2006

I saw a girl at the bank yesterday deposit a traveler's check for $1,000, only to receive a deposit slip back for $100. When she went back to ask where the last zero went, the teller said, "Hmm? But they don't make traveler's checks for $1,000..." Then she checked and learned that yes, they do make traveler's checks for $1,000, and she'd better fix that transaction right quick.

Just an anecdote to illustrate the power and importance of receipts.
posted by limeonaire at 9:53 AM on July 4, 2006

As chef_boyardee explained, you should be okay, but mention it to the manager (or whoever does the daily balancing) so they can double check that day and be sure that it worked out. Give them as much info as possible - card type, date, time of day if you can. This information will make it much easier for them to track it down.

During your cashout at the end of day, you're probably running a daily total sheet off of your credit/debit machine, right? A big long tape that lists every transaction and then the totals by card type. This list is what transactions actually got charged to cards that day.

This tape needs to be compared to what should have been charged to the cards. This number is determined by either a cash register tape that prints daily totals by tender type (you probably run this off at the end of each day, too) OR a receipt book of some sort where you note totals and tender type.

A simple comparison of the receipt book / cash register total (how much $ you should have collected) vs the card machine total (how much $ you actually collected) will tell whether anyone was over charged. If the totals match, you were successful in cancelling the transaction. If there is a discrepancy, the accounting person can take a closer look at the card machine tape to see if there are consecutive charges to the same card number. If this happened, it should be easily located by your manager (or whomever) once they know what they're looking for.

In this case, that's probably a lot more information than you need. Did a receipt print? Did you get a "authorized" message? If no, then you're very likely okay.
posted by raedyn at 10:09 AM on July 4, 2006

If the drawer didn't match at the end of the night a good manager would have found the double charge and then fixed it. This charge would not have stayed on the customers card for long. You might have been called to the carpet to explain the discrepancy.

All of my experiences with credit card machines suggest that no double charge could have happened without the machine getting through to the bank. You're most likely in the clear.
posted by bilabial at 10:22 AM on July 4, 2006