Mtn dishonest sales representatives

I bought 2 cell phones from mtn on a 24 month contract in April 2019. A Huawei PSmart 2019 and an Iphone 7. The phones were on mtn made for me s, i have been getting 350 mb, 100 sms, and 50 voice minutes on both devices. I have been ising one device and the other device i bought for my sister and i am paying R579 for both devices. I am using the device but i am nkt using the mtn contract number for the device full time but my sister uses the mtn number for the device that i gave to her full time. On the 1st of February 2021 i recieved a call from an mtn agent using this number ***, He told me that he has been trying to call me but could not get hold of me so he called the other number and talked to my sister and my sister had given him the number that i use full time so that he can call me.He asked for my ID number and i was reluctant to give him that until he called his supervisor to talk to me, after i spoke to the supervisor i gave him my ID number and he proceeded to tell me that mtn has realised that customers are not using the sms that we get every month on our contract so mtn has a project and they are migrating all customers to where they will take away the 100 sms and replace it with data instead, and he said this meant that if i agree to be migrated i will be payinv R129 per month for each device. It sounded too good to be true so i kept asking him why me, and how come my monthly installment will reduce so much, i had to probe him until he finally came clean and said that if i take this it would be like a continuation or extention of my current contracts, at that point i said no i cannot do that because ive only hot less than 3 months left on my contract and i want to get a new phone when im done paying for the one im using because my screen is cracked, at which point he said, he already spoke to my sister and my sister said she is happy with her phone and would like the R129 per month contract. I said no wait let me talk to my sister when she is back home so he must please call me tomorrow. He said no my sister said she definitely wants this and that's why she gave him my telkom number to call me and speak to me, he could hear that i was sceptical about this and so he told me that i can cancel this at anytime and gave me this number *** where i can call and cancel at anytime. When my sister came home the following day on the 2nd of February 2021 i asked her about it and she said she did not say she wanted to migrate, the guy from mtn just called her and said he was trying to get hold of the person who is responsible for the contracts which is me and so my sister gave him my telkom number and that is the number he called me on. On 3rd of February 2021 i called the number i was given for cancelation, i spoke to a lady and she told me that she has sent the request through for a cancellation. Please note that at no point was i ever told about any fees, the only thing i was told was that i would be paying R129 which would be a reduction from the amount i was paying for my sister's device which is R299. I was very shocked then on the 20th when mtn deducted R2490, 58 from my account. I am distraught about this as i was never told about this amount or any fees, i have only 3 months left on my contract so why would anyone in their right mind agree to pay such an amount, The agent who called was clearly giving false information in order for him to make a sale. I have been trying to contact mtn retentions for several hours a day since the 21st, the phone rings unanswered until they drop the line, i sent an email via the mtn website, the only response i got was them asking for ID number, email address etc but still no further response from them. I would like for them to cancel this new contract as i did call to have it it cancelled and for them to deduct the original amount that i have been paying every month ever since i did buy the phones