Selby Auto S****s operating like ****s

The subsidiary of Bosch Services named Selby Auto S****s has one of the worst service I have ever experience. My car has been in and out of there and they have kept my car for a total of atleast 4 months without fixing it. It is a different excuse every time and it is not like I owe them as my car warranty has approved all claims that they have processed however they are reluctant on fixing my car... every time I call I get given different SLA's and there is no reason for them to not fix my car.. it is now heading into month number 5 without a car that I pay monthly instalments for.. they do not have a sense of urgency and the owner prioritizes other cars before mine, I think it is because I am only 26 and he can spin any story with me.

I once fetched my car out of sheer frustration and it was not fully fixed and then the following week he requested for me to bring it back and it will take a week for him to fully fix it, it has been 5 months now.. I am desperate for my car and they do not seem to symphathize with me.. I use public transport now and also paying a monthly car instalment, please tell me how that is fair