Why not go to the NSA for Clinton emails, FBI Txts?

This is something I have been wondering, the NSA collects all communications of all Americans in all forms, voice, email, texts. Obviously we know that human eyes don't see the vast majority of this information, but it is stored at a massive facility in the state of Utah. When they need to intimidate, threaten, or silence someone, they go in to that person's communications and find something embarrassing and/or potentially career ending. You are kidding yourself if you think that this system is being implemented in a legal or ethical manner. So, my question is, when Hillary's emails went missing, or when Lois Lerners emails went missing, or more recently, when the FBI texts between two Trump hating employees having an affair, went missing does the NSA have the ability to pull the record of these communications? If they can pull John Doe's text messages from 2 years ago, can't they do the same with HRC? Or, are Government secure email and phone systems immune to NSA surveillence? Food for thought!