Problem with support service

All our troubletickets always goes to particular support person because we're from Russia and he is russian-speaking. Unfortunately he doesn't solve our problems but mostly create bigger new ones. He hadn't even read problem description carefully so his answers totally oppose our real cases. How we can change our support person? Should completely eliminate him and immediately move all unresolved troubletickets (and of course newly created later) to someone another. We don't need russian-speaking (said he is only one), english-speaking will be good enough.