Consumer Redressal

I had submitted my Lenovo P-780 smartphone to the Fourtech Computers (HCL - Service providers of Lenovo in Pune) for replacement of the damaged touch screen on 21st January 2014. While accepting the order, I was told that my phone would be repaired in maximum 15 days. I was asked to pay Rs 1000/- as advance. However its been more than 2 months and my phone has not yet been repaired. Each time I call the customer care of Lenovo, I am told that your phone would be repaired in 3/4 working days and that a senior would get back to me in regards to the problem. However nothing happens and not one calls back. I am tired of calling them up to check the status of my phone. Please suggest me what I could do to get back my phone and make them realize about the mental torture that them have given me.