Just got a call from our registration office with the "HUH???" of the day. (Or possibly just the first "HUH???" of the day.)
A student came in saying that he had paid for a class last April, but was now getting collections letters saying that he hadn't paid. Our system showed that indeed he owed the money, and S. asked him to bring a bank statement proving that he'd paid.
He responded that he had paid in that office by cash (that office doesn't take cash), and that he would bring his bank statement to prove it.