My iPhone 4S won't get on the Internet without Wi-Fi?

I have the iPhone 4S and it won't get one the Internet and sometimes won't receive texts without Wi-Fi. I have tried rebooting updating and resetting my settings. On the rare occasion that it does receive or send a text it takes an extremely long time. This problem started just after we switched some lines around to give someone else my upgrade. I use sprint as my service and it started as soon as we switched the lines around and we have taken it into sprint and nothing about the plan has changed.

You might want to check your APN settings on the phone and make sure that they are correct.