Incorrect Contract Upgrade

On the Wednesday 22nd of April I was contacted by Cell C offering to upgrade my contract. The consultant offered me a new Giga20 contract and a new faster ****le. I decided to accept the offer and the consultant informed me that the new contract would take effect on the 1st of May and that the new ****le would be delivered within the next 3 working days. No ****le has been delivered up to now and on the 1st of May when I checked my balance I discovered that my Giga20 is now gone and all that I have on my account is 500MB. I called the helpdesk to find out why I only have 500MB instead of my Giga20 and why my ****le has not yet been delivered. I spoke to a consultant named Jabulani and he informed me that my contract has been upgraded to a 500MB a month contract instead of the Giga20 contract that was offered to me and that I agreed to. I told him that this was Cell C's mistake and I want to cancel the upgrade and go back to my Giga20 Top-up contract I had before. He was unable to deal with my request, he logged my complaint and gave me a ref nr *** and that told me someone would call me within 2 working days. No one has contacted me yet to sort out the mess Cell C created.