Sorry for the delayed reply - I have sadly missed on checking my emails. Look for and remove the app called ONAVO if you have it installed by any chance.
1) Setting > General > Networks > if u seen hotspot option turn it on (if not)
2) Setting > General > Network > Cellular data network > (scroldown) Internet tethering
> enter APN (if this does not work)
3) Setting > General > Network > Cellular data network>(scroldown)internet tethering > Reset Settings.(then enter APN )
If problem still persist, then try and Hard reset the iPad and retry the above.