Just recently had this happen to me. I made a deposit of an 800 check. They credited for 200 dollars then realized it before I did and ‘fixed it’ twice. I ended up with $600 extra in my account. I called and got a robophone nightmare. I emailed them and they responded that they were right and I was wrong. Then about 24 hours later, without emailing me back, they removed the extra money. It was a bit frustrating that I had to deal with a bunch of rigamarole for their mistake. If I were to do it again I would stash it away in a higher yeild savings account and wait for them to sort it out.

Yes, my wife and I did have that very experience.
In 1994 we went on an extended driving vacation, for about two months, and while gone, some small business owner made a depossit of almost one thousand dollars, which went into our checking account by mistake. This deposit according to the dates on our statement, was made in the first week of our trip.
On returning home we noticed that our account had grown more than what our direct deposits would have produced, and when we called the bank to question this fact, they got pissed off at me and locked my account so I could not write checks, or withdraw funds. They kept that account locked for six weeks, and even had their investigators come to my residence and want to know what my intentions were and how I managed to screw up the account. In other words, I was blamed for someone else’s mistake.
It took four months before I was allowed to withdraw that money and get it into another bank, and then only by court order.

The bank ALWAYS will find the mistake. Except if someone deposited money to your account by mistake and never found out….
The bank on the other hand will consider if they are going to fix the error. Sometimes the cost to fix the problem (either cost of money or reputation) is bigger than letting it go…. (in the case that it was a system mistake)
You do not have to inform the bank. It is not a matter of truth… You just have to be prepared that they may ask you the money back….
All of the above are personal experience but not from the customers side….

It is very important that you contact the credit card company, and let them know. Eventually they will catch it, and reverse it. It is always better to be honest about it. I would not wait for them to find it.

somebody made the payment and when it doesnt show up on their statement they will call the credit card company and it will get taken off your statement so go ahead and call them and let them know so.

Contact your credit card company and let them know. They will catch it eventually and it’s always best to be honest.