I just bought a 2 of these from Marketplace. There in great condition, but I can’t do a master reset. When I try to pair them to my Android, it says- device is linked to another account.
I tried to contact the original seller, but he never write back.
If they are linked to another account they are useless, if you can’t get the previous owner to remove them from the account. It’s a security feature to prevent someone from taking over your lock.