I'm not sure about the 'wrong account' scenario, but there was a case last year where Citibank accidentally paid off 'too much' of an outstanding debt to one of

I'm not sure about the 'wrong account' scenario, but there was a case last year where Citibank accidentally paid off 'too much' of an outstanding debt to one of their creditors, and tried to recoup the money in court. They lost. But of course, they legitimately owed the money.