Enginering Design Flaws - Wheel disc and Steering wheel

Tata Motors- Tata Manza design flaws- first front left wheel disc collapses while on road. Since then, the power steering is defective and give severe pain in the right hand arm and shoulder. Both Tata Motors and Prerana Motors have tried to solve the problem over 4 times over the last four months and now seem to have given up. They refuse to even respond to emails now. All this under warranty. Tired of follow up with both Prerana Motora and Tata motors, don't know what to do now.