Here are some possibilities:

scene from movie Contact with Jodie Foster telling governmant official the message was not "person-to-person" and should be released

cartoon: "We sent a message to any extraterrestrial beings in deep space. It was picked up by an observatory in Great Britain. They didn't understand it." cartoon: "As I read it, we're receiving a message from outer space telling us to stop bombarding them with unintelligible messages."
cartoon: "As I understand it, they want an immediate answer. Only trouble is, the message was sent out 3 million years ago." From Sidney Harris, http://www.sciencecartoonsplus.com/originals2.html, see also http://astro.wsu.edu/worthey/astro/html/lec-cartoons.html

cartoon strip: when exterrestrials get transmission of elaborate phone mail message, they decide to blow Earth up.

cartoon: NASA search for extraterrestrial intelligence, "I contacted alpha Centauri..they say that for $29.50 a month, they'll unscramble their signal."