HTC Desire Problems. please help.

Hi guys. My HTC Desire 820 got screwed. I bought it last month as my first android phone, it worked perfectly and I was enjoying it.. I know I've deleted something in it weeks back because now I don't have a keyboard and its not allowing me to download anything, from the playstore or apk. Also, the home button is not working, and lastly its not allowing me to update it to the latest OS. I tried resetting to factory default and the HTC service center people have no idea what to do with it... I know i should go and get a new one but life is a bit hard right now. I need your help. pleaseeeee...