phone calls


I have had a problem that totally mystifies me. Whenever I call a local business on the cell phone I bought here (usually I'm trying to arrange a job interview) there are 5 or 6 rings, then, 3 beeps, and the phone automatically hangs up. This happens when I call the doctor's office or companies that might hire me, but has not happened when I call other indidviduals or businesses. It has happened many times, and I dial the numbers exactly as they are given to me. Is there some way to fix this?