Poor administration and follow up once again.

I agreed to a upgrade telephonically in November 2017 on a data contract at R99/month. The sim card was to be posted to me. I never received it and after numerous phone calls it was eventually received during February 2018. Then I was told that a sim swap needed to be done. After speaking to 2 different agents I was told that they could not do the sim swap. Eventually I decided to cancel this contract as I am being charged for it but have never had any use of it. I then find on my latest statement that I am being charged for this contract. I cannot understand this and after 2 email requests for a refund I have had no response from CellC.