On a prepaid plan with unlimited text and booster for talk and data. The phone is used by my daughter and she is unable to send or receive texts when not on wifi. She is able to make and receive calls. We've tried turning the phone on and off, hard rebooting the phone and checking the settings for messages. The phone is an iPhone 4 so I hope the suggestion is not to pull out the battery and SIM as I've seen suggested elsewhere. The phone was previously with another carrier and we've never experienced this problem before. Suggestions? Thanks in advance.