Telkom - Exorbitant Late Payment Charges

i need to start by saying that I do not have any beef with Telkom, in fact I believe that they are providing very good pricing in our cutthroat telecoms sector. I received my Telkom bill last month and was very concerned about the interest that was charged on my payment being just 3 days late. I was charged R10.75 on a bill of R838. This equates to an annual interest rate in excess of 900%.

After calling Telkom and going through more than 3 consultants (they all didn't know how Telkom calculated late payment interest), I eventually spoke to a manager who confirmed that the rate was in fact 18% per annum.

All I want is to stop this from happening to other people who are not aware on how interest rates are calculated (and therefore being **********) and at the same time putting pressure on Telkom to correct their system.