HTC — Didn't receive my handset from Service centre since 2 months

Address:

Gautam Buddh Nagar, Uttar Pradesh

Hi, I started facing issues with SIM slot, battery backup and earphone jack with my HTC(Desire 820Q) in June'15 so i dropped it at a service centre on 31st July'15, it has been more than 45 days now and i still haven't got my phone back. I called service centre a number of times, every time i got an update that it has been repaired and will be dispatched shortly. It has been 20 days since this update.