Consumer Redressal

I purchased a one plus one on 4th Dec 2014 from Amazon.in with 1 year warranty. The phone mic stopped working on 25th March 2015 and i took the phone to one plus one service center in Borivali WEST. They gave me estimated date of repair completion i.e 3rd April. Its been almost a month i still did not get the handset repaired. I called them up but sometimes they hung up th phone and sometimes they say parts not available. I ve made 5 rounds to the service center but they dont give me any answer or update on the repair status of my phone. Please help me with this. Jobsheet no-JS15032300154