Outraged customer

I just want to express my greatest dissatisfaction with Mtn. In December 2022 I went into the MTN store in Canal Walk cape town to upgraded my sim only contract from R99 p/m to R149 p/m. I was informed by the lady who was doing my contract that at the end of December MTN will deduct R99 and R157 which was a pro rata amount. I agreed to these costs and wrote this information down on my notepad on my fone. On the 16 January 2023 MTN deducted an amount of R408,52 and when I telephonically enquired about this amount today I was told by various MTN consultants this R408,52 includes an early cancelation fee along with itemized billing and 15% vat which was not explained to my on the day when I was at the store taking out this upgrade. There was no contract that was signed so I didn't even get a copy or even a piece of paper to show what costs were involved. I would just like to know who gave MTN the right to go and deduct amounts off my salary that I was not informed of and did not agree to. Today Jane Maruma removed the itemized billing from my account which brought my account back down to R149 which is what was initially the agreement. I would just like to know since when does one no longer receive a contract which is supposed to be a biding document for both parties? And mind you I did request a copy of the contract on the day that I did the upgrade in-store but was told that there's no physical contract and even Jane Maruma today was shocked when I told her this and I refuse to go back to the MTN store because I know for a fact that I will walk out of there even more upset and dissatisfied than what I am right now. I have even requested a copy of a contract even with my last sim only deal and was also told that I could not get one. If you guys cannot give me a contract them please don't ever mess in my salary and deduct amounts that I did not agree to. In fact yall should refund me all the other amounts that were not part of my upgrade because my contact is only supposed to be R149 per month as per your mtn catalogue.