Yesterday I noticed something was scrolling on the display of my HW-Q70T, and it seems it was displaying SHOP6 SHOP NG. Volume also went down to 0, every time on every source. Also my TV (55Q90T) went down to 0, even when the soundbar was disconnected from power source. It took 3 hours, and contact with Samsung to at least solve the issue with the TV. They did a hard reset from remote. I can watch TV with audio again.
Left the soundbar disconnected and tried again, this time I could perform a factory reset, as I had to set up Wifi again. So far, audio doesn't go to 0, but it is still in shop6 mode. When I touch volume down for 10 secs, when powered of, this is still displayed. Samsung is saying I have to sent it over for investigation, as nothing seems to help.
Besides that, I also noticed that it seems I have center audio issue (going to past that separate also, maybe not related). As I was close with my ears to the bar, I noticed that center audio (dialogue) is coming from the center speaker and also from the left speaker, but NOT from the right speaker. I guess this is not normal.
Try With the power off, Press and Hold the Volume Down Button on the soundbar until the display comes on and use the remotes navigation pad/buttons to change the shop mode setting.