Safe to say CM Punk is no happy camper this morning ... after going down in flames to Roman Reigns at WrestleMania 42, the WWE star got into an altercation with a fan, delivering a major smackdown to the man's phone! Punk was captured on video just after midnight Monday, getting into it with the fan, who was filming Punk's WWE friend, Bayley , as she was hugging someone in the lobby of the MGM Grand Hotel & Casino on the Vegas Strip. Check out the footage ... Punk steps right up into the face