Tata Motors Ltd - MANUFACTURING DEFECT IN THE BRAND NEW TATA

We have purchased * Tata Signa **** TK vehicles on **-**-**** and from thereafter one vehicle with Reg. No. TS** TA **** is continously having some ot other issue like, Steering Balloon, Centre Bolt Issue, Axial issue and Fuel Injection Issue and after following up with Tata Motors authorized dealer we have got the issues fixed and then after, there was sudden Engine issue and they have replaced the Engine and also got the Turbo repaired. Its been * months that we have purchased the vehicle, but more than ** % of the days the vehicle was in the workshop. We have approached the dealer for Exchange of vehicle but, they are not willing to do so. Its been very hard for us to maintain the vehicle and pay the EMI's. Please help us out in getting the problem resolved. Every time they resolve the issue and are not sharing any data nor Job card i order not to create the Documents for Evidence. But, all the issues are maintained in the Vehicle History in their system.