I have a customer that is majorly past due (from last season). I didn't continue their service in spring because of nonpayment. I've been sending past dues since last October. I recently sent them a letter saying they needed to pay up, or I was going to have to take it to the next step. They wrote me a letter back claiming we broke their siding, and that's why they never paid us. THIS WAS NEVER BROUGHT UP TO ME UNTIL NOW, ONE YEAR LATER. They claim the damage is insignificant, so they can't find a reputable contractor to do the work replacing it. The letter said "once you find and pay a reputable contractor to repair the siding, we will pay you." I do not like this, this is the second time in my career a non-payer claimed we damaged their house well after the bill was due in order to avoid payment. Last time I let it go, and it still bothers me every time I pass that guy's house. I don't want to let them slide, but realistically is it worth my time doing anything about this? The bill is about $500. If you do think it's worth my time fighting, what CAN I do about it?