I'd deleted my Facebook account years before, but after that begrudgingly signed up to Facebook Messenger because my friends insisted on using it (which are separate accounts apparently).

At some point, a couple of years ago, I decided enough was enough (probably when they forced me to accept some new anti-privacy EULA which otherwise blocked me from using Messenger Lite).

There was no delete account option in the app that I can remember. I searched and searched for at least an hour. Facebook's support site was a labyrinth of circular links that edged around actually deleting my account. I had no Facebook account, so I couldn't log in to delete it on the website's account settings.

I just wanted an email I could send the request to. I finally found one for a data protection officer or some sort. Sent them an email, got another one back redirecting me to the website. Obviously that wasn't helpful, so I sent them one of those GDPR deletion templates.

Didn't hear back, and checking a few months later, my account was still accessible.