Poor service and empty promises

I approached Vip last year about the paint peeling off my bumper. It was a job done by them previously. I went in and showed them and spoke to a gentleman by the name of Allistair he assured me he would help me and arrange a rental. I suggested them paying for as he said they do not have one in the shop. He assured me he would phone me back. I waited a week and called back still have nothing. I am still awaiting the call. I can't use my insurance company as the job was done while I was busy with another insurer. It's 2 months later I have heard nothing the paint is peeling and cracking off my bumper they sprayed and they do nothing. They do not want to pay for the rental vehicle. So i am still waiting for a rental or a solution. I want my car fixed but feels it won't get done as they don't seem to care about the customer. If you don't follow up they do nothing and won't get back to you. It's absolutely poor and I want my bumper fixed