Is a 24 months contract, really 24 months????

Why is my account still being debited while my contract has ended?? This contract was opened in Nov 2017 and is suppose to have been done on Oct 2019 but I was debited.. Why isn't my contract not cancelled since it's finished.. You have no grounds to be debiting my account when there's no contract in place. And harassing me with the calls, I don't want to renew the contract.