Webafrica 25% increase

I installed fiber with Webafrica in March 2020 @ R399 PM for a 10/5 line with openserve. They increased the speed during lock down to 20 which was free. Then I received an e mail to say that the line would change to a 10/10 line at no extra cost on 11 August 2020. I received my bill at the end of September and it had increased to R499 a 25% increase with no notification according to there whattsApp call line Kabelo Theko said it was a standard yearly increase.