I didn't sign for RED Flexi 75 or RED Flexi 200

Receiving an email notifying clients of plans tariff increases on a 2 or 3 year singed for the RED Flexi contracts doesn't seem legal. The contract would list my plan name as RED Flexi 70/185 and now Vodacom just says they're changing the name to a "New Price Plan Names" as RED Flexi 75/200 with a new price which actually deems it a new product(s) and not existing product, the contract states RED Flexi 70 & 185 with my signature or electronic confirmation and I've never signed or electronic confirmed for a product called RED Flexi 75 and 200 that costs R75 per month and R200 per month.

What is a new product? It's a product with a name that isn't part of the current product range and with a different price to other products, meaning these are new products that I haven't signed for nor electronic confirmed.

This would void contract right? Meaning I no longer have a contract RED Flexi 70 / 185 with Vodacom.

The Frequently Ask Questions includes this one "Are you allowed to change the price of my plan?" Maybe yes, but I never signed for RED Flexi 75, so the change in the name and price makes it a new product and one that wasn't signed for. Contract says RED Flexi 70 and RED Flexi 185.

Once my contracts expires I'm not renewing that is for sure, moving provider and porting numbers, starting with the one contract expiring this year.