Uncle Pug says "would you really want this guy to mix trimix for you?"
Thats a really good point, also, if I was another local dive shop would I want to even do a nitrox fill on a tank and valve that this LDS may have O2 serviced? Answer would be NO! It sounds to me this guy is as bad or worse than you say so who knows what corners he has cut. I agree you are far better off without him.