cancellation of cellphone contract

i have been trying to cancel my cellphone contract with vodacom and when i call the number : *** but the number does not go thru. i went to Musgrave and they told me that they can not help i need to call from a vodacom number, i advised them that i lost the simcard and when i call using another network provider the number does not go thru. the contract ended and i need to cancel. i am out of options. i can not be paying for something that has ended. vodacom service is very bad. all i need is to cancel my contract.