you have already deleted the Facebook link in authenticator.
If you backed up the account in authenticator, you can restore it. Or if you saved your Facebook security code you can use it to login, or if you register your phone number you can SMS:
https://www.facebook.com/help/147926301947841?helpref=faq_content
you only other option if Facebook is willing and able, is to turn off MFA (probably not possible) or add an additional MFA method like SMS text (if your phone number is registered).
note: with MFA, you should alway register more than one method, as it is easy to lock yourself out.