Bad communication about contract

My 3 year contract had ended with Netstar, however I had not received any communication ahead the termination of contact. I thought they'd automatically stop or call to ask if I wanted to continue. The following month, they continued to deduct and I'd reverse the money debited. Until a few months later, I get a call from them to say I owe them. How so because my contract has ended. They explained that after the contract, I need to call to cancel. But how because when a contact ends, that must be it! I then arrange to pay what I owe and when I was done, I need it cancelled. A month after my final payment in June, they didn't deduct in July, then August they deducted again, and I reversed again because I certainly told them I don't need their services. September, I received a call telling me I owe them. HOW????!!!! I am super ****ed.