I phoned telkom today and the line rental is the telephony line, DSL bundle is the speed and the 3GB is the usage.
I was checking this thread : http://mybroadband.co.za/vb/showthread.php?p=3460195#post3460195
I wonder if it's better to ask them for a custom deal. 4mbit speed + the 3GB cap I'm currently on. then use afrihost to top up?
Also, I'm on the fast DSL bundle. Is the Faster DSL bundle 512kbits?