Phone question...? help please(:?

so I've had it for a little over a year but my upgrade isn't until next April. it's a palm pixie from sprint and let's just say I haven't necessarily been gentle with it. when I text someone and they reply it comes up blank, when I call someone the screen goes black and I can have the conversation and what not but when I go to hangup the screen won't go back so I have to take out the battery and turn it back on, and the sound like doesn't work even if I flip the switch and change the volume, but it only malfunctions when it's supposed to be ringing, like I can listen to music. and it's just annoying... anything I can do? or what's the problem?