WEBAFRICA SUCKS

We signed up with Webafrica for a fibre internet provider more than 2 years ago. They send a technician to install the connection point for the rooter, he came without the rooter which arrived a couple of days later via courier. We showed him where our existing rooter was but he suggested another place for the connection. When we connected the rooter we found that the installation point was at the wrong place as we do not have internet reception right through the house. We contacted Webafrica to inform them about the problem. Webafrica refused to send out a technician to rectify the problem they insist that we have to buy an extra booster, which we did not accept. They not even once attempted to rectify the problem. As we have reported the problem immediately we then requested to cancel the contract, as we were also within the credit act time frame. Webafrica kept on taking payment on our credit card as we could not stop a credit card transaction. The bank advised us to cancel our credit card in order to stop Webafrica to keep on deducting money from our account. We also send them emails regarding cancellation because we were not able to use the internet. Webafrica just ignored us and keep on sending us invoices. We now have received a legal notice notifiying us that if we do not pay them it will negatively show on our credit record! How can we stop them?