Can I file case on volkswagen about bad service

HI Last year service they damaged my bumper, they said we will fix in your next visit. My recent service nothing was done for damage. After recent service my car getting vibration after 80/100 above speed(they replaced steering rack in warranty). I rase the multiple completes, after that, I got a call from the service station they did something. But the problem is still there. I called customer care regarding this, last week I went to the service station again, they were given 40 to 50K expenditure(like replacing the part take the road test, till problem solve). Because of the last service, I got this problem. Even they don't have clarity about what to do. 2years back I filed a case on Volkswagen about, they sell the car with an old engine(in Telangana, I buy a car from there). So Can I file case on Volkswagen service station again? or add this document to an existing case? http://volkswagen-bad.blogspot.com Where I will get more benefit, please suggest to me. Thanks, Chandra Sheker