My posts in the last 2 days were all deleted. What happened?
If the lead post in a thread is deleted, often the follow-up posts are not strong enough to stand on their own, so they are deleted also. That may be what happened to your posts.
You might keep possibility in mind when posting. Select a subject that is strong enough to stand by itself even if the post to which you are responding is deleted. If material from another post is necessary for a reader to understand your post, then quote that material in your own post. If you do both of those things, and if the post to which you have responded is deleted, then your post will be strong enough to stand on its own.