Reclaiming ownership of a Facebook page can be done in a few simple steps.
First, you need to make sure that the person or organization that currently owns the page no longer has access to it. To do this, log into your Facebook account and navigate to the page settings. From here, remove any existing admins from the page and switch off any third-party app access.
Next, contact Facebook directly by filling out their online form for claiming ownership of a Page. When submitting this form, you will need to provide proof that you have authorization to take over the Page such as proof of business or brand ownership documents or screenshots showing you are an authorized representative of the business/brand in question.
Once your request is approved by Facebook, they will provide access credentials which will allow you to gain full control of your Page. You may also need to submit additional information as part of their security checks before gaining full access.
Reclaiming ownership of a Facebook Page is possible but requires patience and attention when following these steps.