Hey @MelbourneMe, sorry to hear you're having some issues with your service.
If you lose connectivity to your Fixed Broadband connection, your 4G back up service will switch over to the mobile backup/interim service within approximately one to six minutes. More info on our The Optus Ultra WiFi modem with 4G back-up is here Yes Crowd page.
This is dependent on a few factors, it could be possible you have a mobile 4G outage in the area or the NBN isn't fully out. Have you tried to turn off and on your Optus Modem?
Please note that we’re unable to look into account details on Yes Crowd.
If you’re still needing a hand, we recommend messaging us via the My Optus App. The team is available 24/7 and are ready to assist customers as quickly as possible.
Did we answer your question? Please mark it as a Accepted Solution and if you see something that was helpful to you or the rest of the community, giving a Kudos is only a click away.
This is dependent on a few factors, it could be possible you have a mobile 4G outage in the area or the NBN isn't fully out.
Its just as likely its a SIM problem. Either the SIM not being activated or the wrong SIM being issued, with both of those scenarios being not un-common with the Optus 4G backup.