POOR WORKMANSHIP

On the 08.01.2016 I took my car to Cedar Isle Auto for a noisy window when opening and closing on the driver side, I was called during the day and was told the window rubber inside need to be replaced. When collecting the car I did not check the outside of the window, all that I have done was to get inside my car and test the window by opening and closing. I drove the car until on the 23.02.2016 when I booked for my car to fix the heal damage. The guy that was checking the car noticed the rubber from the corner of the window sticking out and asked me what happened and that is when I realised that the outside rubber was not put back probably when Cedar Isle Auto was working on the window. I checked in my car for repairs and thought I will alert them once I got the car back. I waited for almost 7 weeks for my car to be fixed for the hail and a week after I booked my car for service with Cedar Isle Auto and alerted them of the rubber. Now I have been told that the rubber cannot be fixed and the excuse is that the car has been worked on and why I have waited so long. I have tried to explain and this seem to fall on deaf ears. BMW / Cedar Isle think their workmanship is 1000% always