Mistakes happen. But sometimes people are led down the wrong path. In a recent column, I touched on Medicare fraud after being told of a widespread concern in the Lake of the Pines area of Nevada County. Last week, this issue hit home with several seniors in south Nevada County receiving cancellation calls. The calls, which began Dec. 5, were from Healthnet canceling their Medicare Advantage plan as of Dec. 31. The problem is concentrated on zip code 95602 because it appears in two counties: Placer and Nevada. And people in Lake of the Pines have an Auburn mailing address …