MTN BLACK FRIDAY DATA CONTRACT *****

I am highly irrate and furios with the service of MTN. In 2018 I had taken a Black Friday data contract with them for R459 a month. The contract expires now in November 2020. I attempted to upgrade my contract today and have been informed that my bill is R6300.00. How the hell did my bill go from R459 a month to R6300??? They said that I have been charged our of bundle rates as my contract has expired. My contract only expired today hence me trying to upgrade today. I have never once been emailed/smsed/called with any notification of me now being billed out of bundle rates. I will not be paying this bill as I have NEVER consented to this because I was NEVER consulted before MTN took it upon themselves to just bill me as they saw fit. This is highly *********. As a consumer, we have the right to be notified and given options when changes like these have been made. Not to find out this way only when we contact them regarding something else. I have taken out a Black Friday contract with them in 2016 and 2018 and this didnt happen at that time for them to say this is their standard policy etc. I have no choice but to report them to ICASA. They have lost another customer!