We have two Air Rail 1.5 sleeping pads. We have used them about 15 nights over the past 2 years. We are having problems with both the valves. One has always been difficult to close and now I can not close it at all. It simply will not turn. The second will not lock. The stem seems to be moving with the top when I push and turn. 

Do you know of any solutions to these problems? What should we do?