Solved! how to get someone else's facebook account left open off my phone

[keithjhon05]

someone used my phone to access their fb account. Left their account open and it has overtaken my phone . My fb has shut and trying to retrieve it
Messenger is swamped by their multitude of contacts.

 

[hang-the-9]

https/www.facebook.com/help/211990645501187?helpref=page_content