Disgusting is an understatement

I called in April requesting for a cancellation of my contract ( ********** 835) and I spoke to Mpho who provided me with a retention deal of R29 which consisted of 30min, 30 sms and 500MB, however he went and loaded an incorrect deal which was 50min, 50 sms and 100MB. I called in the exact day the incorrect deal was loaded to advise of the mistake and it was rectified. On the 06-05-2018 I received a statement indicating that I am now being charged R64 for the incorrect deal which was loaded as if it was my mistake. I called on the 07-05-2018 and spoke to Pete from Retentions to advise on this ordeal and he advised that he will log the request to the billing department in order for it to be rectified until this day I have not received any feedback. The service is putrid and this is one of the reasons I will be cancelling another one of my contracts that I have with cell c.