Why can't I send/recieve text messages?

I have a blackberry curve. My carrier is U.S. Cellular (cellular one). Every time I try to send a text, it wouldn't go through. It says "Mobile equipment status failed". I try messing with the network but nothing. It started when my network wasn't working and I messed with the wi-fi thingy and now I can't do anything. I'm currently using wi-fi but I wanna use the mobile network so I can browse everywhere and text again. HELP!!!!