MTN South Africa

I've been a customer since around the founding of the company. During all this years I didn't have any problems with MTN until I upgraded my data package online. My payment for March 2023 was R 315 p/m and April's with an increase of 6.3%. That was fine except they've added itemized billing which I never asked for and I never had before. In this case R 16.52 + vat. After I've received the new invoice I've tried to cancel itemized billing wit MTN champions 3 times, it didn't work. One of MTN shops tried to help me trough downgrading the package but result was confusing, they couldn't help me because the system displayed " the client can't afford this exercise " !!!???