Sigh these telkom idiots with their new site(s).
So there's 2 telkom mobile services pages (EDIT: there's 3 actually). The main one (which they ALWAYS send you to),
www.telkommobile.co.za, isn't the one you want.
1. goto
www.telkommobile.co.za/login
There are two options, a green bar "Login instantly" and a blue bar "Login Here". Now, even though you can login instantly, the option for MAC address isn't there. Use the "Login Here" option.
2. Login with you telkom details.
3. Further down the page, there will be a "MyServices" section. Choose your sim which has the WiFi bundle, then enter the MAC address of the device with which you want to use said bundle. So you can enter your laptop's MAC here.
4. To finally connect your laptop to Telkom [Connect]/[Guest]/[whatever they're calling it today], I suggest you visit a telkom store. You need to set the authentication method to... something which escapes my memory right now.