I (homeowner) owe 25% of the remaining contract on a remodel job. There are still a few items left but it is nearing completion. Major subcontractor on the job told me he hasn't been paid even though he completed his portion a month ago. Bad blood currently between them and he doesn't trust he will ever be paid. Contractor's partner called me today and told me to pay subcontractor directly (about half of remaining amount owed). I am happy to do this but am nervous without some sort of paperwork signed by contractor or his partner. Can I write up a contract addendum and ask contractor to sign? Would that protect me adequately if contractor claims I didn't pay full amount? Any particular wording I need to include?