Vodacom is billing me for a cancelled contract

I have been trying to cancel a Vodacom contract from 2019. The supervisor from the Aftersales department mentioned to me that it appears that the contract was cancelled immediately after I requested them to in 2019, but subsequently reinstated. I have since been waiting for the device to be collected. I was assisted by Elisabeth who is now nowhere to be found. It is unfortunate that there is no central point of contact where these things get resolved; I cannot find assistance from any department within Vodacom. What is sad is I get billed on a monthly basis for a service I'm not using. I cannot keep paying this and I want all my money to be paid to me with interest.