Was my favourite provider but m so disappointed in them.

I took a 2 year router contract with them for R270 per month.On the 20th month their signal was so poor, I could hardly use it, I called for a cancellation, they refused to cancel and told me I had to pay for cancellation fees or else I had to upgrade.I had to wait for a further 4 months to be able to cancel.On the 25th month I was puzzled to see that they charged me R600 for the same price plan that was to be R270.I called to question about it and for an immediate cancellation since the contract was over, I was told that m being charged R600 because my contract was over and they were now charging me R600.. Okay I asked for an immediate cancellation which they also refused and told me I was supposed to wait for a further one month and pay that R600 for the following month.. Now I was not able to pay for that other for something I could not use because of their poor network and my credit score is being affected.I regret taking their contract.