Being Mislead by MTN sale person

I was mislead by the mtn sales deparment , I had contract with mtn sale person called me to offer me a deal , the told me that its was great deal becuase currently i was payment R299.99 the told me if I take the deal i will be paying R499.00 including my initial contract and agreed. Today when i receive my bill its R1070.00 and i call to ask again whats happening with my bill why its R1070.00 they said to me that is the once fee. Then asked again how much i will be paying the following month the told me R299 +R499 if new the deal was i would take it at the first place i dont have the budget for that. They deal the home rooter on 31 March 2022 even today its working I told i want to cancell the cancel the contract of the rooter because is not working for me they told me that i should have cancelled 10days ago and transfering me to another consultent to another and i am not getting any help. I felt misled by mtn sales person and I have be a loyal customer for mtn for years now but shold the do to me. What they did is so unfair. They told me about cancelling fee, cancelling the even connecting , What must I do , must i stay with the that is no working for me apart from being misled, MTN I am not happy at .