Are you using the FB app, or website?
If you're using the website, it's likely to be similar to Samsung Members website. After a period of time you will get logged out & need to login again.
Also like Samsung Members app, once you are logged in, you don't have to login again, & your session does not expire.
I'm not surprised, that if you tried to contact Facebook's help directly you would be waiting.
But I would think that any community forum, similar to Samsung Members, would be far more helpful.