Non cancellation of contract

Hi, i took contract with vodacom in october 2017 for 2 mobiles under one contract and its ended october 2019 so i called the contact centre to cancel the both numbers and move it to prepaid. I spoke to a female and she cancelled one number and left the other number on month to month plan without my consent. I only came to know about this 8 months later when i visited a local Vodacom shop and they said i must contact the cancellations department and i spoke to numerous consultants and they did nothing about this query as it is gone 1 year now that the contract supposed to be cancelled and its not. Its affected my credit score tremendously. Im in arrears for r3500 which is not my fault and its the agents fault who supposed to do the cancellations properly. They are escalating my query from the time i found out my account was in arrears and i didnt receive any notification that someone in Vodacom is actioning it, spoke to a consultant yesterday which she **** and said that the contract was cancelled because of my trust issues with Vodacom i actually spoke to another gentlemen and he said the previous lady **** and the contract is still active and is in arrears. Im really frustrated with Vodacom and i would never recommend anyone to use they services again