Cancellation Service Provider Terrible

I have tried to cancel a contract I spoken to 2 individuals and they have both said it’s been canceled yet now 2 months bills have been charged for a contract that I have cancelled that I don’t not want. You give numbers to contact but I get cut off I go into a store and get told they don’t do cancellations in store I must phone a specific number yet I do all of it and the same things happen I am tired of this back and forth wasting my time and energy on a pathetic service provider. All I want is to cancel a contract.