my stroke has to go back to the shop, its thier fault

If this guy doesn't stand behind his work now I wouldn't even consider using his services again.He's not competent,you'll just be buying more problem's in the future.If it were mine and couldn't get some satisfaction out of this idiot,I'd disassemble it and clean and inspect it and reassemble with what was needed.Then bad mouth this guy to anyone who'd listen.