I worked for this employer for only a few months and quit on short notice (this is in the US btw). Almost two months after leaving they are saying I owe them $700 because they paid for benefits I used while not working there (true but common when an employee quits/is terminated) and because they paid me past my end date (not my fault or my mistake). Do I have any grounds to refuse payment? My concern is I don’t want them to forward it to a collection agency if left unresolved. I’m trying to buy a house and want my credit to remain unchanged. Any insights are appreciated! certified letter here