MTN Promotional Data Issue

I just would like to thank MTN for spoiling my december as if 2020 was not bad enough.

I have a data contract that had 100gb+100gb promotional data, my contract now ends in november, i have been charged R2800 for prorata data.

my spend limit is on R0 firstly My MTNChoice 50GB is my default package which should be R999, how can you charge me for the next 3 months?

How does this fit in with NCR rules and my affordability ?

I called the call center, my contract has not expired as yet, and still nobody can help me.