Their authentication server apparently is set to allow only 1 or 2 connections. Its also very liekly that your session did not terminate and is still active(although unuseable). Phone Telkom Internet and ask them to clear your sessions, you will need to tell them your username. Once you get thru to them and a semi competant person should take 1-3 minutes if its just that.
Edit:
Also just make sure your username and pwd is correct. A power cut can corrupt settings tho i think its not as likely but worth checking.
well sessions auto drop after 24hrs (or less if set by isp). Reason i said phone them to clear sessions is due to me reading alot of complaints recently of Ti acc. that have concurrent connect set to 1 and i know disrupted connects don't always clear.