Poor service

My insure Auto & General requested that for my crash and dent to be repaired by Auto Magic in Limbro park, my car was there for 6 days, yesterday when I went to fetch my car the boot was no longer closing, now they making excuses that central lock and the alarm is faulty that is why the boot is not closing anymore while I took the car and it was fine and one of their assessor Sello confirm that it was working when brought the car, now they making excuses not to take responsibility of fixing my boot, I want boot fixed immediately