Facebook Account Already Linked to Another City? Can't Restore My Old Progress

Every time I try to connect my Facebook account to restore my progress, I get this message:

"[Sorry, Mayor!] This account is already linked to another city. We cannot log you in to this account."

The thing is, my Facebook account is linked to my old city, where I had made a lot of progress. I've never had this issue before and was always able to log in normally.

Has anyone experienced this before or found a fix? I'm worried about losing my old city. Any help would be appreciated.