Cancelling thousands of dollars in loans for a previous year (therefore, not my error) which I tried to save by contacting the students. There is no going back: it's done, finito, fini...dilly ding dang done.
But, I bet they get the letter telling them they owe the institution money, even though numerous contact attempts to get a new promissory note went unanswered.
I was able to save a few of them who responded.