Hi there ,
if thats the case i would highly suggest to call TPG support as they may need to send a tech over to fix it. It shouldnt do that if theres no issue with the NTD. You can reach them at 131423 option 2 + 2.
I had a similar problem. My computer was connected to the modem via ethernet cable, but my wirless was on too, and the computer was trying to connect via the two methods resulting in frequent dropouts. The problem was solved by simply unplugging the ethernet cable and using just wireless.
I checked your account and was not able to detect any issues on the network. I can organise a call from our Tech team to look into it further for us to understand the problem. Please send us a message of your preferred time and best number to be contacted.