Why can't I get on internet when on the phone shouldn't have to use WF
Welcome to iMore! As VDub2174 stated, try cycling airplane mode. A couple of other things to try:
1. Perform a soft reset by holding down the power button and home button simultaneously until you see the Apple boot logo.
2. Reset network settings. Go to Settings > General > Reset > Reset Network Settings. Keep in mind you will have to set up your wifi again once you're at home or anywhere where you normally have a wifi connection.
3. See if there is a carrier update available. Go to Settings > General > About. If there's an update your phone will prompt you to install the carrier update. If nothing pops up within about 30 second then your carrier information is probably up to date already.