Instagram and Facebook

I have just started working for a new company and the owner has opened millions of facebook accounts and instagram accounts covering every aspect and permientation of the business name. I am trying to sort it all out. to one facebook business page and one instagram account. One thing he did was open a facebook account under the business name and then link that account to the main instagram page we use.
Facebook has now stopped access to this account as it is not a real person so I am trying to link the instagram account to the proper business page. When I unlink the account on instagram it does this fine, but as soon as I attempt to link facebook again it just automatically links to this account we can't access.
I would prefer not to restart the instagram page as there is a lot of followers on this one and it is producing us business. I cannot seem to find anyway to access the facebook page it is linked to. Facebook have stopped access but the page is still up.
Cannot link instagram from the correct Facebook page as it says that instagram account is already linked (even when I unlink on Instagram).
Feeling like I am going around in circles.
Help?