Number upgraded before time

Good morning I have a problem, i app**** for a contract on the 15/11/2017 taking two Huawei P8 Lite 2017 @ R149 X 24 MONTHS for each phone. The contract was approved. I was helped by a consultant by the name of Innocentia Molema who helped me very nicely and explained everything to me accordingly. She explained the 7days exchanging policy, 6 months warranty policy and 24 months guarantee policy and she offered for insurance which i didn't take. She even explained that this is a 24 months contract, i can upgrade on the 20th month of my contract, the deal was sealed as i was happy with the service Innocentia offered. Payment started in Dec 2017 everthing was fine i was paying R300.00 every month for these two phones, it went well unti i went to the store to add the third phone which was approved aswell. Come the November 2018 invoice i'm told i need to pay R1207.43 i became curious and when they check my invoices i was told that the ********** 113 number, month sub is R859.00 and i asked how cause i pay R149.00. I then came back when Innocentia was at work and requested for the paper work, which she looked and found it and when i check i signed for R149 X 24 months not R859.00. She said she needs to escalate the matter which she did and gave me a REF# when i did a follow up they take me from pillar to post, finally when it was checked she said the is a department called Retension who did an upgrade on my number when my contract was only nine months, then i recalled that the first time i app**** i was told i can only upgrade on the 20th month not 9th month, i have all the ref numbers that Innocentia logged. Now she calls me that i must go and do an affidavit that i didn't request for an upgrade and i will not do that because i once went and did the affidavit when there was two numbers *****ulantly added on my contract that was in Jan 2019. So im tired of going to MTN Westgate B to complain about the amount on my contract. So as much as the Upgrade was done by that department (retensions) they will have to reverse that upgrade and the money that MTN says i owe them cause i pay what i signed for every month, you can check my account on your system... ********** 629 R149 x 24months, ********** 956 R199 x 24months and ********** 113 is R149 x 24months not R859.00.... The Ref # that Innocentia gave me everytime i go to the store i still have them. Innocentia tried everything in her power to deal with this and she is not getting any help from head office and she is very helpful because she knows everything about this query, so can any superior help the consultant as mush as she tried to help me, REF: 1- ********** 4587, 1- ********** 4588, 1- ********** 5928, 1- ********** 3551, 1- ********** 6336, 1- ********** 3577, 1- ********** 1749... this is all the Ref numbers that where given to me. And this gives me bad payment record when i try to apply for anything i'm told that i don't pat MTN well i need this resolved today......