Nissan Motors — I'm complaining about my nissan sunny vehicle

Address:

714/2, THUKLVAKAM VILLAGE., Chittoor, Andhra Pradesh, 517520

My nissan sunny vehicle was met with an accident on 06/02/2019. And i have given my vehicle for service in cjn hi-tech moters pvt, ltd. At tirupathi and the service manager has promised me saying that from the date of work starts he will deliver my car with in two months but now its almost three months is running they have not yet delivered my car and the service manager is not responding me properly and they not answer my calls and they dont intimate the work progress too. And they asked me for advance payment as i havent heared from any other service points. And mean while they told me that they charge me 250/- per day if i dont take deliver once the vehicle is ready, so its almost three months they have not yet completed the work, who is responsible for this issue??? They speak all about their rules and timings as its delay from their side and irresponsible people of service, so what kind of help can nissan company provide me.