My reply might be a bit too late. I had the same issue and neither dlink nor tpg could help and spent a whole two weeks doing trial and error. Odd thing is the modem would only connect via "ethernet" connection instead of the vdsl/nbn option that my previous dlink modem had used. Connection on mine now works great. Only issue I sort of have is having to reconnect to the internet everytime I reboot the modem.
