Eighteen years running trips out of Tupiza, with local guides and drivers rather than staff brought in from La Paz — which on the four-day crossing to Uyuni is the whole game, because the route runs through country where the driver's judgement about a river ford is the safety system.
The website is published in English, Spanish and Portuguese, which tells you where the customers come from. They publish a landline and a mobile; the WhatsApp is the mobile.
They publish no street address, so the pin here is the town centre.