Welcome to TPG Community!
We were able to locate your account using your community details and have run some remote test, but was not able to detect any fault.
Have you tried to turn Off and On the NBN box or NTD (Network Termination Device)? Refer to this link for the image of it.
Once done, try to call the number again. Keep us posted if it's working or not and we'll arrange a call from our Tech team to look into it further.