If you don't want your phone number or credit card number posted, don't post it... that's pretty basic security.
You have the ability to delete the post when first made, but after a user has responded, you cannot delete the post. Hopefully you can understand that if your post was deleted, and people have responded, and then new users come along and cannot see what was originally responded to, this would cause chaos. This is the "purpose" of a forum, to share ideas and get answers to questions.
This is how forums work. Without posts, there would be no forums at all, and you wouldn't be here reading this now.
Just so you'll also know. Yes you can format your drive, but did you know that "EVERYTHING" you send or post in cyberspace is there permanently? It's true it is. Your emails are a "permanent" record as well.
Welcome to the internet!
P.S. As a matter of courtesy to all of our members, please refrain from posting obscene words in your future posts. Once again, thank you in advance for your cooperation.