If your payment was late and it was canceled, that is their right. They may still come back on you though and make you pay a fee and the late charges. I think there is nothing you can do but hope they forget about you. I would think if you want a cell phone then you need to find another provider.
I would think you would want to prevent that from happening by working out some type of payment arrangement with them. Usually they like to work with you if you're in hardship and see you are trying to be a responsible customer. This should prevent you from being cancelled. However, if you do get to that point, you have no choice but to abide by the contract rules and pay the disconnect fee, your late payment, and whatever else you agreed to when you signed the contract.
Contact the service provider through sos message