Vodacom contract nightmare

I bought a contract Iphone 6 in March from Vodacom accessories in Greenstone from Noluyanda. Only for me to be sharing a number with someone else, i have been querying the issue since December the 20th 2018, as my number has been blocked to accomodate the other person with the same number (seems to have been a duplicate sim card). I have been in communication with Mbuyiseni Mthembu from call centre who has now left me hanging after a few calls and emails promising that he will call me back, sent me to the store to get the contract and only for him to tell me it doesn't have the information he requires, dealing with rude sales consultants while at it in the store. I have left him emails and i have received no feedback. Im currently sitting with no phone number as it has been blocked and i have received no assistance till today. I have stopped paying the account and i have still received no help. I would love to cancel this contract as it is such an inconvenience and the service that has been provided is a horror.