Sorry to hear that and not a good beginning to the season.
There is NO excuse for an electrician to do this. Happens a lot every year unfortunately. It says right on the face of the receptacle that it is 30 amps, 120 volts and it would have said that also on the packaging for it. The guy made a negligent assumption. An electrician is a licensed professional and the one ultimately responsible to ensure the work complies with code and is safe, not the homeowner.
I would start with the electrician. Often they will man up and take responsibility. If it went before Judge Judy, she'd call him a blind idiot and make him fully liable. If it were me, I would talk to the local electrical inspector and see what they say.
If the insurance company will cover it, they have the right to subrogate the claim and they may or may not go after the electrician. You don't want to your insur. premium to go up.
You won't won't know what's damaged until everything is checked. Some get lucky and some don't and costs them thousands to repair everything. If something 120V wasn't energized (water heater, ex.) it will be okay. Things like fridge, AC unit, microwave and converter will be suspect.
