MTN not actioning contract upgrade request until billing date passes

It’s now the second time I receive the very same pathetic service from MTN. I had a 40gb data contract for R199 ending 5 June 2021. A week before end date I got a call to upgrade to 60gb for the same amount and I aggreed and accepted the contract on the phone. I never got any feedback regarding the status of the upgrade, I was surprised when I got an sms saying I will now be paying R1200 for 40gb, I called MTN to enquire about the sms that’s when I learned that the upgrade application was cancelled and I was never given feedback then I was advised to do another upgrade before 12 which is the billing date. I was then assisted by Thandeka Mdlovu on the 8 th to do the upgrade application she requested documents for the application, which I provided after the call with her, and she promised to contact me back. Until today 17 June, she has never called me back. She delayed from her side the 12 th which is the billing date has passed. I called and went to MTN branch, they can’t assist me because it’s only her that can proceed with the application because it’s status says pending. Thandeka Mdlovu is not responding to my emails I called their call center and they are refusing to transfer me to her. So now who must pay the R 1200 for data received when I requested an upgrade before my contract lapsed and MTN not actioning the requested upgrade delaying until after the billing date has passed?