hi all I have a hire purchase with first response finance we brought in October 2014, had a few weeks and it developed a problem the trader took it back and (seemingly) fixed it, again a few weeks later again it developed the same fault so he agreed to fix it, in all it went back 4/5 times to be fixed all seemed fine until two weeks ago when the same thing happened this time I have said to first response I want it to either go to a garage with no connection to the trader (seeing as it has a recurring fault that he has supposed to of fixed) or my preferred action would be for me to hand the car back and given a full refund for the car. they asked for me to provide proof the car isn't fit for purpose with a diagnostics from an independent garage which I have done in three different ways but they say this isn't good enough every time I provider it they say its not good enough. the fault is with the turbo which isn't working and according to the garage I normally use hasn't worked since I brought the car, I don't know what to do next im paying over £50 per week for a car I cant use at the moment any advice please