What's happened is that the pole has worn in the place where the clamp is most often closed to when doing downstairs work. Working downstairs always puts the most wear and strain on clamps and sections as they are often used sideways instead of vertically when they are doing high work. A simple way to cure this is to get some rapid setting epoxy resin and smear a very thin amount on the worn area, allow to dry and sand smooth. This should sort you out.