They disappear because you don't pay the fee. They are limited visibility posts. I can't help you. You must pay the fee for a permanent post, or stop posting.

siggy47

Friend, I would even pay a fee, but there are publications of mine that sometimes don't even appear and end up disappearing, making it difficult for me to continue sharing content, so could you help me with this and I will pay the fee?

sdtyv

BooksAndArticles

Computer Networking: A Top-Down Approach, 7th Edition

You have a good idea regarding the books, but you are gaming the system. I pay for the territory, and you're not paying the very nominal fee I have set for you to post.