We often communicate with Facebook support and sometimes we are given effective instructions that we are happy to share with our subscribers.
Here are detailed instructions on how to claim admin rights on Facebook Business Manager if you have lost access to it or someone has taken it over.
To get started you will need:
A scan of a valid identification document of the person who signed the application. Here are examples of documents that Facebook accepts: https://www.facebook.com/help/159096464162185
a) A description of how you are associated with this Business Manager (and the reason for the administrator change).
b) The name of the person who currently owns the Business Manager (the Business Manager's Administrator).
c) The relationship of the person described above to the Business Manager.
d) An explanation of the reason for the request, such as proof of termination and an explanation of that person's relationship to the business.
e) All documents supporting your request, (if applicable specify: death certificate or statement from a lawyer about the transfer of rights to the Business Manager)
f) A link to the Facebook profile (or email address linked to that profile) of the person you wish to add as the new Administrator on the Business Manager.
The following phrase should be included in the application (it is important not to change it, but to write it as it is written here)
I hereby certify that the information I have provided is true and accurate, and I am aware of the liability under the law for knowingly providing false information by me.
It is also desirable (but not necessary) to translate the statement into English. The above phrase in English is as follows: I declare, under penalty of perjury that the information you have provided is true and accurate.
The last 3 payments from the advertising account and the last 4 digits of the card (if there were no debits and/or the card is not attached - just enter so)
All this information will need to be transferred to a specialist from Facebook ad-cabinet support with a detailed description of your situation.