Fed up with Vodacoms customer service

It has taken them more than 2 months for my contract to be cancelled. The Vodacom shops can't help you. You also get numerous reference No's. My contract is still not cancelled from end January 2019. My contract officially ended end of February but still I get charged even after I've personally given notice quite a few times. They give me the credit when I call but still I am not on pay as you go. I want to use the best options available to me without being bound by a contract. I am a pensioner.