people piggybacking on by site

When you say “post over” what you’ve written, what exactly is being changed? Is the text in your posts being changed, or are these comments that are being added, or something else? Can you post an example of a page/post that’s had this happen?

The text is not being changed and they are not comments being added. It is as if they were posting a new blog so it appears first and you have to scroll down to mine. Before I erased them there were 30 of these “posts” all in foreign slavic it seemed languages.

Your site has been hacked.
Notify your web host.
Change your CPanel, MySQL passwords
Change your WordPress password
Update WordPress and any plugins your might be running.
Delete any unknown or suspicious WordPress users.

Resources for hacked sites:

https://codex.www.ads-software.com/FAQ_My_site_was_hacked
https://www.ads-software.com/support/topic/268083#post-1065779
https://smackdown.blogsblogsblogs.com/2008/06/24/how-to-completely-clean-your-hacked-wordpress-installation/
https://ottopress.com/2009/hacked-wordpress-backdoors/

Additional Resources:
https://sitecheck.sucuri.net/scanner/
https://www.unmaskparasites.com/
https://blog.sucuri.net/2012/03/wordpress-understanding-its-true-vulnerability.html