Forced to pay while Telkom delay install

I ordered ADSL from WebAfrica in January. The line was installed on the 23rd Jan but I was told afterward that Telkom do not have spare ADSL ports yet. Following up with Telkom, they say I must wait for other clients to cancel their line before I will be allowed ADSL. I asked why I must pay line rental for a line I cannot use (I do not have a hand phone) and Telkom said that if I want to keep my place in the queue, I must keep paying. They also apparently are not willing to increase available slots and forcing me to pay their 'bribe' money to keep my place in queue to hopefully one day have a chance at ADSL. How can this be legal?