car antenna cover and topper came off at car wash . no radio reception
I believe this is what the bottom of your antenna looks like. you will need to buy a new one. because even if they found it at the car wash the electrical circuits got wet and probably ruined it. If you kept your receipt from the car wash you can try going back and see if they will cover the cost of a new one. It never hurts to ask, but you probably would have had better luck if you told them right when it happened.
Topper? Did you send a vehicle through a car wash with a luggage container on the roof?