Telkom is a ********** company, they try to ***** money

Telkom has been sending me ********** invoices expecting me to pay R 3000 instead of the amount which I agreed to for R 807 or else they will cut off my internet connection. I have been battling with them to correct the invoices since June 2019 and they are still sending me these invoices with large amounts. I did not agree to have the line speed increased and I did not agree to any other amount to be charged. They have a poor customer service and will mostly drop the call or keep you on hold for hours but they will in no way attempt to assist you even after contacting the CEO. I have demanded on various occasions that they cancel my contract but they do not want me to because I'm a paying customer and they will lose money. Their prices for the fibre connection were dropped a little but I clearly have not been included in this as the new amount is R 600 some odd, but I am still being billed incorrectly.