Stop Loss Always Failed to Execute

My stop loss never went through, no matter how many times I set my stop loss level it always failed to execute. This is odd because I keep checking it, but the charts can sometimes be very choppy, and then suddenly I lose more than I intended. I have already talked to their customer service and they keep on saying they will call me back after they 'investigate' it. But here I am, 3 months later, and still no callback. I am really getting tired of this whole thing. I have given them all the information they need. Why is this happening to so many people out there?