Sony India — Having a major problem in my sony xperia c5

Address:	Mumbai City, Maharashtra, 400004
Website:	support.sonymobile.com

Hello sir i had purchase sony xperia C5 on 11/3/2016 and wanted to replace the mobile as since i have purchase it had some or the other problem i have to visit service center 4 time. in that 1 times for display changes and now for 2 times for network problem please suggest me how to replace the cell phone what are the procedure for it.every time they are telling there is software problem but it is not solving i had missed my many important call and having lots of loss in my buissness