Plan exchange enquiry

I recently entered into an agreement for a cellphone deal at the Maponya Mall store in Soweto. I was assisted by a lady called Dorothy. She loaded me onto an incorrect plan (more expensive plan). I went to the store numerous times and even her millions of times (with my airtime) and in all occasions I am promised a phone call but at the end of the day I end up being the one calling and driving, and on 2 occasions, all the way from PTA simply because I sometimes don't get satisfactory feedback from her . I tried to be reasonable but its clear that either she or the company just has no respect its customers. I have been told not to use the sim which I will be charged for on my due date which I feel is absurd. It is now the 8th day i am busy with this query and even today the consultant promised to phone me back in a few minutes but hours later it hasn't happened.