About 21,000 AT&T Wireless workers could walk off the job as soon as Monday, WZVN reports The Communications Workers of America union gave the company 72-hours notice Friday of a possible walk out.CWA members have been working on a rolling extension of their previous labor contract since early February. They have yet to strike a deal with AT&T."We have given AT&T every opportunity to show their commitment to finding common ground and a fair contract," said Dennis Trainor, vice president of CWA District 1. "Time is running out for AT&T to stop undermining good jobs, quality customer service and its long-term success. The pieces are all in place now, and we'll strike if necessary."