Uninstall the device from device manager if needed/possible and restart Bluetooth service.
Start > services.msc
Right-click "Bluetooth Support Service."
Choose Automatic.
Go to device manager and right-click on your computer name and click "Scan for hardware changes"
Install the Bluetooth device drivers from the manufacturer's website, if any.
If the device isn’t showing under device manager or under show hidden devices then shutdown the pc, unplug the power cable & then reconnect, then go to device manager & see if there’s any unknown devices showing, if so uninstall this & then scan for hardware changes & hopefully Bluetooth will reappear.