Cell C Supervisor not willing to assist with Cancellation

After feeling like I have no other way to resolve this I have resoluted to posting on here. I called Cell C on the 1st of October to cancel my LTE package which was on a month-to-month agreement. The call centre agent mentioned that it would only be cancelled on the 30th of November, I reminded her that I was on a month-to-month and that the agreement (which I have in my possession) clearly stated that I only had to give 20 days notice. I also made it very clear that I wanted my package to be terminated on the 31st October and did not want to be billed for November. The agent then said that her Supervisor (Siphokazi) would call be back to resolve the matter. Since then I have called back so many times and every agent tells me that they are unable to get hold of Siphokazi and that they have sent an email for her to call me back as apparently only she will be able to resolve this due to the original call being logged under her. We are on the 7th of November and my LTE package is still active and Siphokazi has still not called me back.