Way back I went over accidentally, got a snotty letter saying they weren't aware I had overdraft facility's with them, I paid up and put more money into the account.
Later they put £10000.00 into the account and took it out again, so I wrote them a tongue in cheek letter saying I wasn't aware I had given then permission to use my account for money laundering and would they please stop.
Got a letter back apologizing and £25.00 for the inconvenience.