Having issues with my iPhone 4S?

Okay so on Monday (May 13, 2013) my iPhone 4S stopped working. It would only let me send iMessages and Internet using Wi-Fi, like I'm doing now. Then the next morning I tried calling on my phone and it said it couldn't connect to the Sprint network… So I took it in on Tuesday. They said they just put my number on a different phone in my account. So now I can text and call perfectly fine using Sprint signal but then when I go to Instagram and the safari app… It says "Could not activate cellular data network. You are not subscribed to a cellular data service" but I'm I've texted my friends and they see my texts and they can text me back and I can see it. So I called the woman at Sprint and she told me don't worry you just need to wait 2 hours for your signal to come back then you need to call ##update# to fix the problem. Well I waited and waited and it never came back and when I did the ##update# it failed. So I just want to know if this has happened to anyone else, because I really don't want to go back to Sprint tomorrow because I know they'll reset my phone and I'll lose all my text messages. I don't want to lose them. So does anyone know of a way for me to fix this on my own? I heard I should restore it. Will that fix the problem or do I HAVE to take it back in?

Go to general - reset - reset network settings
It won't delete anything from your phone but you'll have to put your Wi-Fi password in again.
The same thing happens to my phone so that's what I do. Hope it works for you!