I sorta just tuned in to this.
The link says
The Brazilian newspaper O Globo reported on Tuesday that the Legacy, which was carrying seven Americans, disobeyed a control tower order to descend to a lower altitude before coming into contact with Gol airlines Flight 1907.
It said the Legacy flew at 37,000 feet (11,300 meters) to the capital Brasilia, but then ignored an order to descend to 36,000 (11,000 meters) feet to continue its flight to the Amazon city of Manaus.
Brings up a few questions. One, were they in radio contact with the "control tower" (at 37K? Should be ARTCC but sometimes in SA the functions are combined)?
If they were in radio contact and were directed to descend, did they acknowledge the transmission? IE: Did they get the message?
If they were NOT in radio contact, I would assume the route altitudes are on the chart and the chart would have shown the alt change at Brasilia for the leg to Manaus.
In short, before I start blaming folks, I'd just like to know a little more.
As one who has flown SA routes, it's not as easy..by far... as flying CONUS or even Europe. There are language problems (accents primarily) and, in general, there's a lot more you get off the charts than via radio. Ya gotta pay very close attention to both radios and charts.