you need to think of what you will do if you need another piston in the future. wiseco will have standard overbore sizes. "cutting down" a piston should not be an option. to alter something like a piston is asking for trouble. it sounds like they need to press in the correct sleeve (94mm) or give you a new jug. they screwed up, not you. just my two cents.
Agreed, have them get you a new cylinder. Then send it off to Eric Gorr and get it bored and replated like it should have been. Steel sleeves are old technology.