what is FRC1-MOBI and why does itshow up as a bluetooth connection option?

Check if this remains connected even when you walk away to another room with concrete walls or say 100 feet away.

Try the following that may help remove the mysterious device

• Settings > General > Transfer & Reset iPhone > Reset > Reset Network Settings.
• You may have some third-party apps installed especially for Audio, please delete that.
• You may have some profiles installed by some nearby Bluetooth accessories.

I tried looking that up but couldn't see an exact match.

Are there any other devices near you that offer Bluetooth features? I know that when I look at Bluetooth in Settings I see other devices such as a keyboard on another computer. It could also be a TV near you. You may be able to narrow this down by walking around. I know that my Bluetooth signal drops radically when I walk into another room.