Diamond keypad problems.. replacement?

[zlilz]

I bought a used Sprint Diamond off someone on craigslist. After about a day, the keypad stopped working. The button does light up when pressed, but the phone doesn't respond. I thought it might have been a loose connection so I opened up the phone but I didn't see anything. Does anyone know where I can buy a keypad? Or do I have to get the phone fixed through Sprint/HTC?

Thanks