Sorry to hear this happen. I don't know how a licensed electrician can do this, but they do. There's no excuse because the 30A receptacle is clearly marked for 120 volt use only and is marked on
all TT-30R receptacles. This is the sort of thing that can potentially electrocute people.
Anything that runs on 120V and was energized at the time is likely damaged. When this happens, it can get very expensive. The electrician is clearly at fault and if he balks at it, I would contact the local electrical inspection authority. If the guy was not licensed and said he was, he is in big trouble and you should definitely contact the inspection dept.
