Deleted post still shows on facebook link

I had a test post with dummy text when I first set up my site. I have added new content and made the site live 2 days ago. Since then deleted the test post, emptied it out of the trash, deleted all pictures I had relating to that post and cleared cache.

When I (or anyone else), copy my site URL and paste into Facebook, the deleted dummy text shows with the thumbnail. When I click the link, the site looks exactly how it should but I can’t get rid of this dummy text when I link my URL. What am I missing?

Anyone had this issue before and how did you resolve it? Thanks in advance.