Miway is a *******

I had a new windscreen fitted in my car through Miway, I then experienced the worst I have ever imagined, when the sun is hot I burn like am roasted, so much that the air con in the car is not doing justice at all, I went back to Miway they told me they will get back to which they did not, instead they sent a message to the Glass people who in turn want to be paid. Here is the issue though Miway is not willing to get to the bottom of the matter they are telling the other guys that they only cover the glass nothing else but my issue now is yess the glass with all that was in my glass initially, My car came full house with those protections against the sun. Now do I stay with Miway to continue ripping me off? everytime I have to take the initiative to push Miway to do right. This is absurd