JC: I suggest dropping the mediator and continue w small claims. Get large (8×10) pics showing contractor damaging pipe and practice your persuasive speech laying out your claim in ~5min. Bring in the higher estimate of a repair.
Draw a easy to read timeline of events for judge to see. Dates,times phone calls, letters: who said what and when.
Something to keep in mind is small claims courts tend to like to see actual cost receipts. ie. you pay for the fix and are suing for reimbursement.
I would wait until you have a judgement, and he does not pay, before contacting his CO.
You also need to prove $600 repair did nor fix problem. ie Statement from plumber or better yet, bring him into court.
