I have the iphone 4s and I am also having the same problem. I talked to customer service and they assisted me and got it working once however, two hours later I had the same problem.
then again it could always boil down to a network issue as well..so for giggles post the closest cross streets and zip to where youre having the issue with data or reception so it can be ruled out.
current work around is to pull up the dial pad..type in ##clear# then hit call..tap ok at the resetting subscriber settings prompt..let the phone cycle and do its thing..once you see the 3G or 4G logo at the top try your data out again and post what you see.
Thank you for your post. I am sorry for the delay in response. Are you still having issues with your phone? I can help.
Sprint Social Care Team
I updated my phone to the ios 7 last night and now I can not make or receive any calls. Texting is working. How can I fix this?