I had the same problem with my phone. I called sprint they put me on the phone with HTC due to the fact that HTC gives you a one year warranty, HTC wanted me to send them my phone and there would be a month long turn around. So I called Sprint back, ended up speaking with a manager I told them I cant be without my phone for a month so they put a note on my account that they would credit my account the cost to have the phone repaired at a Sprint store. I went to the sprint store and told them about the note on my account, they fixed my phone in about 5 mins free of charge. Anyway long and short of it call sprint untill you find someone helpful.
I basicaly followed this post
here