Shadow bans are when you can see and post but no one else can see your posts.
I'm not sure what you mean about no info about deleting posts? My understanding is a ban will not necessarily stop you from seeing the community, but it does unsubscribe you. There is an option to remove posts/comments when banning someone. I can't speak to what would cause you to not be able to view the community at all. Do you want to post a screenshot to trouble shoot?
I can still your see older comments in the community. The screenshot is meant to demonstrate how you can search for them as well, it's not the only comment there.

(I don't have a .ml account, so I'm not logged in but I am searching directly from the lemmy.ml web interface because sometimes federation means searching from one's own instance is a bit behind.)
If I understand what you have said in this thread, you posted once and it disappeared (corresponding to the "removed posts" mod log) and then you posted it again. I'm assuming that's what the ban was about, and the ban could also remove the post.
We're both just speculating. I think if you want certainty, it would be a good idea to message the mods or the instance admin for more info.