Vodacom- terrible service

My personal information was compromised by Vodacom, and a ********** contract upgrade was done on the 9th January 2018. I followed the procedure and ***** was confirmed on the 29th of January 2018. I have been trying to cancel this contract ever since with the same story of escalating the issue. I spoke to a lady by the name of Boitumelo twice last week and each time she promises to call me back. Today I asked the gentleman who was assisting me to transfer me to a manager instead he put me on hold then hanged up after about 8min. I have complained to the complains e-mail that also promises feedback in 48hrs. I am all out of ideas on how to get through to Vodacom to cancel this contract an d convert it to pre paid. Vodacom is the most expensive network with the worst service level.