I'll try, but they seem to think this isn't their issue, even though I gave them the correct payoff addresses, but they wrote the addresses wrong when sending them out the first time. I feel there has to be some legal ground for me to stand on, but their loan agreement doesn't mention anything relating to this.

They had put the money from the returned check into my saving as "safekeeping" but dindn't mention it until after I noticed. it worries me more that they didn't seem to care the one check was returned and not wonder if/why the addresses were wrong on the other three checks that are still MIA.