By Phil Wahba (Reuters) - J.C. Penney Co Inc, recognizing it made mistakes in its attempt to re-invent itself last year, launched a social media and television campaign on Wednesday that asked shoppers who left in droves to come back. Last year, sales plunged 25 percent after recently ousted Chief Executive Ron Johnson largely eliminated the use of coupons and sales in favor of regular, low prices. It was a disastrous move that alienated Penney shoppers who were accustomed to expecting coupons and deals. Penney posted a video on Facebook featuring images of classic J.C. ...