Cancelation of Router data contract

Router data contract terminated at the end of February 2020. I phoned customer care cancelation of contracts to cancel the contract. Person who I spoke to assured me that the last payment will be at the end of March 2020. On the 16th of April I received my account by email and was still billed for the router contract. I phoned customer care cancelations and where not satisfied with the answers. I send an email to customer care pertaining the cancelation of the contract. They answered me back with a email that the matter will be investigated and problem rectified. Needles to say this never happened and we are already in July and Vodacom keep on billing me for the router contract. I have made in total 6 calls to the customer care division regarding this problem and send 3 emails and received 3 emails that the problem are being addressed with no result.I have in total received 5 reference numbers which are: ***; ***; ***; *** and the last one 00249aFDWMXVQ8F9. One of the worst companies to do business with and a customer care division which actually doesn’t excist.