They LIE, MISSLEAD and BATE and SWITCH.
The cheap flights advertised are not available. They will say that you have to "be flexible" meaning that the dates, airlines and times will change, and (in my case) cost 3 x more than they advertised. They have exorbitant charges for refunds, and when you ask for one, they will transfer you to different people who try to convince you to just pay more for a "full fare" flight. They are a SCAM.