Support Problems

I have a bad problem with my UR-816C audio card. I asked for support through email on July 25. Today is August 1. Nobody answered, at present. I wonder whether online really exists or it is a crude fake.
When opening the the driver facility control, a waring appers stating that an audio program works with the card, so no change can be done using the USB check options. But there is non audio program using the card, actually!
When I tried to update the firmware, the firmare app warns that there is non card connected to the PC.
Take note that I use Cubase 10.5, but also Reaper and Band in a box. The trouble started after Band in a box crashed.
I have uninstalled both the UR-816C Toolkit and Steinberg Yamaha Driver applications. After this I shut down the PC, re-opened and I installed again the Toolkit including the Driver (TOOLS_for_URC_V110_Win). Now Cubase and Reaper recognizes the card.
However, the Audiocard Control facility does not allow to change USB mode, anyway. The following warning still appears:
“Please quit the application using the audio device to change USB mode”.
Take note that NO application is apparently open in my windows 64bit PC (cheched using Ctl+Alt+Del command in Win10).
Accordingly, I cannot update the card firmware to V101.