Telkom is ripping us off

I feel because Telkom has the monopoly in RSA they are ripping us off. They bill for a telephone line on a fibre line and I connot get it removed. My package is 100mbs of which I have never had a “speedtest” of more than 75 mbs. For the last 48 hours nearly 10 hours had no as in none internet connection. For the last 24 hours I had between 5 and 30 mbs. We had to run this contract through a third party and I feel this is unacceptable. You can phone Telkom six times a day and the remark is they will see what they can do. If you refuse to pay they threaten you with the law and credit burua. What are we to do?