I would like to warm MTN contract users to follow up on their contracts before they get billed 6 times the amount they are paying.

I was paying R325.56 for my MTN choice 10gb plan which can with promotional data. The contract ended and I was not aware since the sim stays in the router. I was billed R1769.31 For the 10gb + the 30 promotional data without any form of communication. Customer service just said I lost the discounts because I did not call to terminate or upgrade my account. I have a prepaid MTN number and no one called.