Strange though: How can a provider prevent you from switching Internet off on your phone? It’s like the water company preventing you from turning off a water faucet in your house. 
What I’m saying is, your local software should take precedence: The provider provides a service, you should be able to enable or disable it locally (obviously if the provider doesn’t provide it, enabling it wouldn’t change anything, much like turning a faucet on when there is no water in the pipes).
Oh well.