delete post works perfectly

reduces post/like count accordingly

 

The only time you will not be able to delete your post is if it is the first post in a thread ... you cannot delete it then.

 

How can you delete a thread?

 

That requires using the Report button and getting the admins to delete it.
The same holds for changing a thread title- if you make a typo or want different wording in your title, use the report button.

 

How do I delete someone else's posts?

 

You should be able to edit the OP to replace all of the text by the word "deleted" for example. Of course this leaves evidence that you originally made a post there.