Cannot get through to contact centre

My car was broken into in June this year, and I asked my insurance company (MiWay) to have the passenger back window replaced. They arranged for a technician from 24fix to replace the window. The technician ended up breaking the winding mechanism, which they had to replace. The next technician could not assist as the repairs had to be done by a VW dealership, which we had done about two weeks ago. Over the weekend, we discovered that the window is broken again. I've called 24fix a few times, only to be kept on hold until I eventually hang up as I do not have the time or money to waste. They have diligently followed up on the issue over the months, yet when I need to contact them they are unreachable. We were told by VW that they do not guarantee parts not bought by them, so I need 24fix to buy an ORIGINAL part to have it put in so that we don't go through this again. It's been 4 months and this window issue has not been resolved, every time I get a call from 24fix or Miway it's to ask if the car can be taken for tinting but I can't do that if the window is broken. I NEED THIS MATTER RESOLVED WITH URGENCY MY PATIENCE IS RUNNING DRY!!!