Agila Wheel Bolts Spins on Brake

Hello together, have just tried to switch from winter to summer bikes at the Agila the woman. Then the following problem appeared for me insoluble: The wheels at the Agila are fixed with nuts, the standing bolts are stuck in the rear brake drum, looks like an inpressed multi-tooth. Now a mother is so stuck that when the bolt is released, the bolt turns along. This happened to me at a rear and a front rim. So I did not get rid of the wheels. Is there something to do? Does anyone have a tip? Can a bolt be “attached” in the workshop again or has to be a new brake drum for the rear and a new one for the front …., I have not been able to see exactly how the bolt is fixed in the front. Does anyone have a tip / idea? Thank you very much.