Wrong selling

I'm very disappointed with MTN. I took a contract telephonically with them last month and the sales person was not truthful to me, she said the contract will cost me R409 for the cell phone and R469 for the laptop only to find that on my pay day R2000 was deducted from my account. I asked them what's all this now but they took their time to respond only 2 days ago the responded and told me about pro-rata that I was never informed about by the consultant. I want my money back and they should cancel all this contracts otherwise I'm going to the umbuds man because this is wrong selling and against the NCA. I was never gonna take that contract if I was told that they will deduct R2000 because I can't afford that much based on my expenses.