My cell phone wont send/receive data, Please Help!?

I have a Samsung Intensity and its a Prepaid (Verizon), and up until recently it worked fine. Now it will not send/receive MMS, and it times out trying to connect to mobile web (even tho I paid 99c for a 24hr period) and it won't connect to any Verizon apps (ringtones, pix etc..) Anyone else experience a problem like this? Is there anyway to fix it? I tried resetting it and re-activating it and nothing works!!