This happened to me twice, but it was twitter (long before Musk took over).
They held my account hostage in exchange to my phone number - which I refused to give them.
Despite the ban, their system still sent me their annoying newsletter. It also took me 3 support tickets to get my account deleted and stop receiv8ng emails.
This happened to me when I signed up again to report a fraudster in my local area's subreddit. I was instantly shaddowbanned, without any messages or warnings sent to me.
I was unable to post or up/down vote. I contacted their 'support' over it and just got all my messages ignored, or maybe they weren't even received.
On the flip side of this, my main account was banned there but my alt account that I've also had for a few years now wasn't. And I've even made a post or two with it there in the months since my main was banned, just to see.
And the funny thing is, the last time I was a banned for a few days (I managed to successfully appeal), they also banned my alt account that I had never even posted on before. Then unbanned it along with my main account after my appeal. So clearly their systems are aware that the two accounts are the same person.
Reddit held my account hostage too. I wasn’t allowed back in until providing an email. They claimed ‘suspicious activity’ or something like that and framed it all as a service to me. I gave them an unused address that I set up for a community group years ago. The reddit account in question was over a decade old.