Telkom Business Invoice Misrepresent your account

We signed up to SupremeCall R10 000 whereby we pre-pay R10 000 each month to receive discounted call costs. When we were sold this product by Telkom reps we were informed that any unused balance would be carried forward to the next month - it was at first . Apparently they changed this policy last year and informed all businesses - not a call or registered mail. Having noticed a year later than my account was only carrying over 35% of unused costs - this equates to +- R2000 a month or 20% of our pre-payment not carrying forward. This has cotinued for more than a year - you would think they would phone us to tell us. The real issue I have with this, and why it was not picked up was the invoice we receive from Telkom shows the closing balance each month and does not anywhere show that this was not the amount carried forward to next month. It also shows the savings we achieved by using this product. Both of these amounts are completely wrong and misrepresented. This amount is not carried forward and being on this product did not give us this saving. This is gross misrepresentation and I am sure the Cusumer Protection Act and the Advertising Complaint Authority will deal with this