Sony — SONY ZL NOT WORKING AFTER LOLLIPOP UPDATE

I would like to complaint about one of your products which i owns of SONY. I have a Mobile phone(Sony Xperia ZL- C6502 -SL NO[protected] and i have been using it for more than one and a half year also the same was working properly since last saturday when i received the software update from Sony . As usual, i ve downloaded the same and installed it in ma mobile but after installation phone went shutdown . I powered on the mobile after plugging into the charger and the same came back with the new lolipop software but after a few minutes the same began to restart . At first the mobile works for a few minutes and then restarts afterwords it started continuously restarting . As a customer i visited one of your service centers in Edapally(Ernakulam, Kerala) and they said they will check and revert . After two days they called me stating that the motherboard of the mobile has got damaged and they are not able to service the same. I ve asked whether they have checked the motherboard but their reply was they don't do hardware service in there only Software service are to be done there.The next option for me as per them is to either buy a new phone or they were saying about an offer in which i will get replacement for the mobile with half the price of the mobile launching price. Please explain to me how come your service center finalized that motherboard of my mobile has gone faulty without checking the hardware part. The said mobile was working a few hours before updating to lollipop . Please suggest what should i do, Now ma phone is not working becouse of one update which sony has provided and even your team is not ready to get a solution for the same. I am very dis-appointed with the service of sony as my mobile gone damaged due to the software update provided from the company and even your team is not at all helping and now i am in a situation to buy a new phone due to such pathetic product and service.