The rate books available will depend on the TNG version you are running.
To see which rate books is available on TNG, you can log into TNG and go the Trunk Line Configuration page. Click on the drop-down under the 'Ratebook' column to see the list of ratebooks.
For TNG (South-Africa) by default the Telkom rate book will be assigned. You can however assign a ratebook per trunk line or change the default ratebook:
NOTE: If TNG does not include your ratebook, you also have the option to setup your own custom ratebook. Refer to forum post: TNG Custom Rate Configuration and Format