Making me pay for services that I did not use or receive.

I have had rain from last year working smoothly using their network. It was pay as you go, I pay I receive their unlimited data. If I don't pay they stop the data. Now I am no longer need their services so I stopped paying and they stopped their data. But to my surprise they said I have outstanding I owe them monthly payments and it is not a monthly contract. They said I still have to pay for subscription even if I don't receive their services. Day light *******. I am not going to pay for services that I did not use . I asked them to provide me with an agreement that I signed to that they can't provide me with that. I am being forced to use their services even when I don't. Because to my understanding if I pay then they must provide me with their unlimited data continuesly so. I f I want to stop I will still have to continue paying.