Ran a credit card yesterday for around $700.00. Customer not here, so just running the number, and the first time I tried, it said, 'NO MATCH'. I exited and tried again, with the same result. Finally tried a different zip code, and it worked. Printed a slip for the exact amount, and I thought all was good. This morning, the statement settlement showed over $2100.00, so call the number on the card terminal. Turns out that all three attempts went through. They referred me to our bank, who said that we had to run the refund ourselves. Did that, then had to call our customer. On top of apologizing, had to warn her that the refund won't apply for 7-10 business days. I said, 'I really hope you weren't planning a big vacation right away', and she said, 'Well, yes. As a matter of fact, we are.' But it's in July, so this should be cleared by then. So embarrassing. First time customer, too. This happened once last year, too. Doubled the lady's bill, after we exited a seemingly failed transaction attempt. How can we know for sure it's failed or didn't go through, so there are no repeats? Should we sit with it longer and wait to see what happens?