MTN Poor Service and *********** staff

I tried to cancel my cellphone contract today but the sales lady (I forgot her name) at MTN Cancellations Department tells me the contract is locked and I am unable to even request a quotation to cancel. I request the Supervisor she says hold on, after a while she says sorry you are able to cancel the contract however you have to pay R4000 penalty fee, mind you that the contract ends at the end of June 2020 and I am paying R350 on a monthly basis. How did this stupid lady came to the conclusion one may never know. So I said may I request a formal email of the quote DOLOLO till now. MTN, I understand cancellation = loss of revenue and the mandate is for customers not to cancel however take note that this processes are there to be followed and please you can't have people who are so so *********** serving the customers.