I am sorry to know that you're having dropouts to your service. I've seen that you have been in contact with one of our Technicians and this has been raised to our Engineering Team. Based on our Engineering Team's assessment the caused of dropouts was the modem/router itself and a replacement for your modem/router has been approved. I sent you a Private Message for more details.
Let me know should you require further assistance.
If you wish to get a 3rd party modem/router you can check the list on this thread.
List of compatible and NOT compatible NBN FTTB/FTTN modems
Thanks to @tonystork