Welcome to TPG Community!
We apologise for the inconvenience caused by the connection issue.
I've seen that the issue has now been escalated to our Engineering Team and is still investigating the cause. Furthermore, I've done some remote tests and it already appears that your modem is connected now for almost 24hrs.
If you're still experiencing issues with the service, please do let us know so we can inform our Engineering Team and have them to contact you regarding this concern.