Blacklisted with no explanation.

I signed a price lock contract with multichoice December 2017. For 3 months, not once did i pay R539 as promised. If it's not R765 it's R886, I've called so many times but no can explain what's going on, not even the team leader on duty. They disconnect me because i refused to pay anything more than what's stated on the contract. I called, cancelled and paid my outstanding fee. Now they have blacklisted me, in debt of R4760. I've been calling since January 2019, no can still explain.

Can Multichoice kindly fix this and clear my name, since no one knows what's going on.