Overcharging and very unhelpful

I signed up for Vodacom fibre in about October 2019 and the experience was terrible, I was paying about R500 per month prior for LTE but was assured fibre 'was much better'. It was shockingly bad and the only solution that Vodacom was offer to upgrade the package to R899 per month and it would 'be much better'. Not only is it not better, it either goes down 2-3 times a day and is extremely slow but they also charge me R1450 per month when my contract is R899 per month. Despite numerous attempts to explain nothing gets resolved, 1 month it was 'it must be installation', next was 'we charge extra for the first few months', 'are you sure this is not the amount you agreed to'?? I am not sure the contact centre know what they are doing at times it feels more like an excuse line to fob you off for another month.

Bottom line - The fibre connection is much worse than LTE for more money and they are charging me R500 per month more than my contract says.

Is it even legal? I have know idea what it will be like when I try to cancel the order.