My windscreen damaged by Technicians

Hi<br> <br> The technicians replaced my windscreen and they did a really bad job. The windscreen rubber has been falling off ever since they replaced it which is problem I never had before. The windscreen rubber is stuck on with a Glue and has damaged my painting, this is supposed to be put under the windscreen not use Glue to stick it on. I have been calling tirelessly, they promise to call me back and they don't. I am really frustrated and annoyed by the their level of service. I need them to fix it or give me a refund so that I can go to another service provider to sort out the mess on my car. I have been in contact with a lady called Natasha and she prromises to get back and never does so I guess I need to sort this out myself, but I need my money.