Worst Customer Service and Network provider

They increased the amounts on my account without my consent. My account went from R560 in November to R700 in December to R834 in January saying that they increased my speed without asking. I canceled my wifi due to the lack of service provided. My wifi had no internet access more than it ever did have internet access. I called in twice for support on the lack of network and was told there was nothing they can do. Now they refuse to correct the payment account error because "You already used the increased speed during December so you must pay". I offered to pay the original account amount and they refused again stating there is nothing they can do. By far the worst network provider I have ever dealt with.