HTC — Bad service and making or fraud

Address:	Lucknow, Uttar Pradesh
Website:	htc.com/contact/email.

I have purchased HTC desire 620 g phone on 22jan 2015. I was facing problem in my phone so I sibmited it on the service centre, they changed my phone mother board n they damaged my phone too. They told that g sensor is damaged. They again repaired the phone and changer the mother board again . When I called on there service no they told Mei that they have changed my charger not mother board or any thing. Afterwards they told that my phone is replaced .now the phone is damaged and they are not replacing it. I am mentally disturbed, pls help me