Debit order limit

I took out an ADSL package for R799 / month in March. The first debit order goes off my account for only R500. I leave it because I thought it was less due to pro rata. The second debit order again goes off for only R500. I call the Telkom call center who advise me that there is a debit order limit of only R500. Which in itself is completely stupid, as I the customer purchased a package for R799 a month yet only get debitted R500. While on that call to the call center, I request that the debit order limit get increased to R800 / month. I manually paid the shortfall via EFT, which brought the account up-to-date. Now I find out that Telkom have listed me on the credit bureaus as a late/bad payer!!!!! This is extremely unfair as it was never my fault to begin with. Telkom set the limit lower than what package I took out! I want my name cleared ASAP!