In order to disconnect your Wantedly profile from your facebook account, you will need to delete your Wantedly account and register a new account using your email address.
Your can delete your account here: Delete Account
It may take about a week for your account to be deleted. Please note that deleting your account will erase all of your information.
If you are still having trouble, contact Wantedly Customer Relations Team from here!
Sorry for the inconvenience :(