3 weeks ago I purchased a Samsung Galaxy Watch LTE on a plan. I did some research and was told by both Samsung and Optus support that I shouldn't have any issue with my Pixel 3 (Running Android 10) connecting to it. However, out of the box, I was getting an error message of "The Optus network is not compatible with your watch when attempting to connect to LTE. (This was all done instore) We tried to connect it to a Samsung s10 and it still did not work, all other features work on the watch work with my Phone. After this, I was told to contact Samsung tech support. I got in contact with a level 2 almost a week of trying. They said Optus had not set it up properly. Optus has just said they can't do anything. Assuming the issues is not resolved soon the only thing I can think of is making a complaint to the ombudsman. Optus said I was told it may not work (They never said that) and refused to allow and exit or further assistants.
Any help or advice would be great at this point as I'm not getting anywhere going instore.
I thought all of the newer model Android handsets would have been compatible but Optus specifically says "Samsung Galaxy Devices" here - https://www.optus.com.au/for-you/support/answer?id=20003&typeId=2
Assuming their content is up to date and correct (I'm not certain it is), then you'll likely have to go down the path of lodging a complaint directly with Optus or via the TIO as you've mentioned. You can lodge a complaint with Optus directly via the link below:
If my original thoughts are correct though and your device is compatible, I would be asking for them to completely deactivate number share on your account. Once that is completed (only Optus can do this), start the process over via the wearable app on your Pixel. This fixes a couple of other issues that occur as well so I think it could help with your situation.