#1: I hope you’re not ccommiting the worst type of onaah here.
#2: The Gemora answers he should do tzorchei rabim. An interesting story recently (printed in ish l’reiahu) about a guy who got stuck. A guy drove by and fixed his car. Had all the tools etc. He was a repentent mehanic doing tzorchei rabim to return.
#3: a story with R. Zemel of Volozin. I don’t remember the details. Bottom line was, from the Gra, if one really really does teshuvah and all he can to repay, it will be placed in the other persons heart to forgive.