Facebook disabled, linked to Instagram

Someone disabled my Facebook by linking it to a bogus Instagram account. I tried using the "wrongfully disabled" form under the Help center but it won't send because it says I need to login, which obviously I cannot. Help please if anyone has experience with this.
Here is the message I get while trying to get anywhere on FB:

Your account has been disabled
You cannot use Facebook or Messenger because your linked Instagram account nguyen.vietkhai.1592 is disabled. Activity on nguyen.vietkhai.1592 goes against Instagram's Community Guidelines or other standards.If you think your accounts were disabled by mistake, you can request a review of the decision on Instagram. To find out more visit the Instagram Help Center.
Visit Instagram Help Center
Would so appreciate any ideas!