Refusal to lower Subscription Fee even when Contract has long expired

I have a problem with my ISP, Home-Connect. Our contract has since expired and I called them to request to be charged a lower rate as they now charge R688 instead of R711 subscription fee that they charge me on the month to month contract and they refused. All they say I have signed up for the R711 contract which they agree has long expired but they don't want to charge a lower fee that is advertized.

How on earth are they still referring to a contract that has since expired? They unfairly charging me more while sticking on the contract that has expired this is day-light ******* as I cannot understand why am I being charged more than their current subscription fee. All their agents that call are just calling to make me accept the over-priced expired contract based subscription fee. I am being ******** here. https://www.home-connect.co.za/fibre-to-the-home/frogfoot-fibre/#packages