The literal meaning of "you are mean" is "you are unkind". In this context, especially if it's a playful comment, it means "I expected a little more sympathy from you!"
Your advice about calling a policeman was fine, but without "Oh, I'm sorry to hear that!" or something else sympathetic, your advice sounded a little like "Well, just deal with it. I don't care." Did you remember to add a smiley face? :)