Vodacom cancellations

I have been trying to cancel a three year cell phone contract. I have been a client of Vodacom since I bought my first cell phone more than 10 years ago. I have visited several branches where I have been told that it must be done telephonically. I have tried for days to contact the call centre at ***. Only the call centre is allowed to change or cancel the contract. They just don't answer. Nobody at Vodacom can advise me on an alternative way to do the changes I require. The only conclusion I can make is that is deliberate. If you want to cancel or down grade you are frustrated. Vodacom is *** I believe all this id done purposefully to frastruste customers until they give up, and would urge anyone else to consider other service providers when looking for a cell contract.