24 MONTHS CONTRACT??? what a joke

Dear Vodacom, What is the point of signing a 24 month contract if you want to cancel a month after the contract was supposed to expire, Only to be told that the contract ends when a customer calls the call centre, then when you cancel the contract, Vodacom still wants to debit 2 more instalments (for unknown reasons). This is not right at all, YOU SIGN A 24-MONTH CONTRACT, NOT AN OPEN CONTRACT THATS LASTS UNTILL THE CUSTOMER MUST CALL AND CANCELL I want this expired contract cancelled without any further instalments deducted!!!!!!