Vodacom increasing contract payment with no formal communication.

I was checking my Vodacom invoice and statement (as I normally do), and realized that the payment amount was higher than normal. I made a call to the Vodacom Customer Care Centre this afternoon and the agent I spoke to told me that the reason my debit order amount is suddenly higher is because of Vodacom's 'price increases on contracts'.

I have not received ANY communication regarding a price increase whether by SMS or email from Vodacom and the agent confirmed that there was no communication sent to me to advise me that my payments will increase effective from a certain date. Am I supposed to just be okay with my debit order amount being increased with no communication? Because I am not. How can I be okay with suddenly paying higher when I was not informed that I will have to start paying more, a responsibility Vodacom holds.

Vodacom's service is absolutely **********, I cannot believe the amount of issues I have had with this network!!!