Iphone 4s, Can't access internet away from Wi-Fi?

Whenever I use my iphone 4 internet away from a Wi-Fi network it pops up saying "Could Not Activate Cellular Data Network! You are not subscribed to a cellular data service'' I have tried restoring and changing the cellular data settings, 3G settings and Wi-Fi settings. I recently came back from overseas and since then it hasn't been working?

You need to call your cellular provider and inform them of your location change. They will change settings on your phone through their network that will make it function properly in the location you currently are in now. There's nothing that you can do to fix it yourself as it is not broken, just set for a different location.

Make sure you are subscribed to a data plan on your iPhone. If not this will happen. If the problem persists, then I would call your data provider. Sometimes, they are unhelpful, so I would read online to see what is wrong.

You need a legit data plan from your carrier