Sony — Sony xperia c3 phone

I had bought a Sony xperia C3 phone on August 2015.. I had started facing problems within 3days. I submitted my phone to the service centre and then at the service centre i requested for a replacement but they didnot. They just did factory reset. They again I started having problem from the next day, I visited the kalpatru service centre kolkata, they kept my phone and changed it's Motherboard.. Then after 15days approx again I started facing problem they he changed my mother board again and my back and front pannel which changed my IMEI no.. Then again my phone started having issues then they changed my battery.. Even my earphone has been left.. Now tell me instead of changing all these they could have changed my phone! I trusted SONY but it has dissappointed me badly. I've been harassed so much..! This is the 3rd motherboard, 2nd battery, 2nd earphone nd 2nd front nd back pannel.. Now again I'm facing major issues in this phone! I'm not going to visit anymore service centre because it doesn't add to any solution but just harassment! SONY is taking my issue very lightly and just asking me to visit the service centre over and over again which is not adding any solution to me! I want a replacement or my money back! I've complained many times but they are taking it very casually! So please resolve my problem as soon as possible because it's out of my tolerance now!