Vodacom Fibre - Increase rates and packages as they wish

I received an email from Vodacom yesterday that my fibre link is being 'Optimized' from 25Mb for R649 to 250Mb for R929. This is crazy as I don't need that super fast speed at that super high subscription .. How can they simply make a blanket rule for me to be further indebted. Fact is I cannot afford such a high fee. I called Customer Support on *** and was basically told it was a business decision and that if I cannot afford the subscription I should cancel my line .. So, take it or leave it, no mercy. They were instructed by business to not even log a ticket for these complaints, and from what I can gather is that they are inundated with calls complaining about this. This is hugely unfair and I wonder if this action is not in contravention with the NCA. Where is my protection not to be unfairly indebted.