I have recently started yet another new job (I do a variety of part-time jobs) and got paid last month. They paid me what I know is far too much, so I phoned them and politely pointed this out, and asked them to let me know exactly how much of it was overpayment and how to repay it.
They haven't asked for it back yet.
Tonight I did some more work for them, and politely pointed out to the person I did the work for that they hadn't asked for the money back yet, nor had they advised me how much they had overpaid me. She said that there had been a mix up and they would be sorting it out, but they haven't, yet.
Is there a point at which they can't ask for it back any more?