I had same problem, although the original remote still worked sometimes.. Could not find replacement. I did buy a generic learning remote (15 euro) and managed the squeeze out the last signal of the original remote to help learn the new remote.Need a replacement remote...
I got my Yarra3DX through Indegogo, not Kickstarter, and Indegogo no longer has any reference to Yarra3Dx / Comhear. Although I do have other Kickstarter campaigns Yarra3Dx was not one of them so I can't access any Yarra3dx-related info from Kickstarter; this (forum) is my only connection to Yarra 3Dx info.
I've been using the unit since June 2019 and am rather pleased with it; it sits atop my 65" LG OLED. I've added a second sub, a Canton 10" active, to the small sub that comes with the Yarra; it adds needed bottom end.
But now, the remote vol+ button stopped working, requiring I connect via Bluetooth, which is a nuisance.
Any advice on where I can find a replacement? As posted elsewhere, Yarra3dx.com web page is suspended, and Comhear only offers a phone number.