The two best ideas are to get a device that plays the phone company's tones for the "This number has been disconnected and is no longer in service" message. Sometimes, the call spammer's war dialer will flag your number to be removed from the call list. The other good idea is jsharr's - waste as much of their time as you can. They are not making any money talking to you.
All reports I have heard about that trail are excellent. Outdoor Idaho did a segment on the trail. It should be available somewhere in there online video catalog.
http://idahoptv.org/outdoors/shows/myexcellentadventure/turn.cfm
I have not yet done that trail. I would either have to do it in sections or try to find someone else that wanted to ride it in order to set up a shuttle.
It is hard to fine them when they are calling from Kazahkstan. Most of them come via the internet and out of the US. They would be out of business fairly quickly if no one ever gave them any money or information.
If you are referring to this location:
There is Brundage Mountain, and Tamarack to the south:
http://tamarackidaho.com/summer-activities/mountain-biking
http://tamarackidaho.com/summer-activities/mountain-biking/bike-park-information-and-hours
I had to wait for a few of those to cross the road last weekend in Yellowstone. The traffic this weekend was of the non-motorized variety in Teton Park. The road looked like the I-405 at rush hour, except with bikes and cars. There were more cars parked at the trailhead, and down the road to Windy Point than I have ever seen before.
Several dozen bison, some ducks, crows, and geese, 2 coyotes, and 1 elk in Yellowstone Park.
46 miles from West Yellowstone to Beryl Spring and back. 43-48 degrees, alternating clouds and sun, mostly light winds.
These days most bike manufacturers use Henry Ford's color scheme - any color you want as long as it is black. Contrasting lettering seems to be the only option.