At the bottom of CONTACT US page mine (i am in sydney) says:
Prefer a landline number? Call +61 2 9007 3023
I have the same issue as you, I'm about to call it now..
Not sure if it says a local number to ur area.
i changed +61 to "0" and was able to call tpg locally 02 9007 3023 from landline (i have no mobile phone)
they ran some tests still no go needs tech
Cheers i never even noticed that at the bottom of the page