Most frustrating part about no name brand like this is there is no support or instructions for troubleshooting of any kind. There is no company website or any kind of warranty. This should be treated as an overpriced dollar store purchase.
In short, there is a button that switches between bluetooth and USB dongle. blue light shines for BT and red for USB. When mouse stopped connecting, the ability to switch between bands stopped as well. Unit failed internally and is unresponsive. More junk to add to the global garbage pile.