Forced to pay for their system and process errors

Someone please advise on legal steps to take here. Why should i pay for their process and system error? I'm disconnected and it took two weeks of talking to different people daily to even get why. Where can i report this because i feel as a consumer im not treated faily.

This is what was said to me.

Our records indicate in March 2019 your DStv account was incorrectly credited with the amount of R329.45, not that you did not pay, however, the payments we received thereafter for the subscription due were short payments.

The account remained active as the result of the credit, making it seem like the account was up to date. Our finance department was reversing the incorrect credits on accounts that were not supposed to have been credited.

Your DStv account was one of the accounts that had an incorrect credit. When the billing was then rectified and credit reversed, this left the account with a balance still due for payment.

Currently there is an amount of R534.47, due for payment to ensure the account is paid up till the 30.08.2019.

Then, monthly subscription of R494.00, will be due for payment on the 31.08.2019.

We apologise for any inconvenience that may have been caused.