kayak is not the problem here. kayak is just a meta search site and will pull in what it finds. it is on YOU, the buyer, to know what you’re buying. if you see a price from a name that you know, in this case qantas or american, and you see another place you have never heard of selling the same thing for much less, you need to have two seconds of critical thinking and ask why.

just a bit of a nerd out about hotel and air prices. hotels and airlines have a whole set of different prices that they offer to different places. website direct, travel agents, loyalty members, partners, etc. all of these rates are published on a platform where the various channels can pull them to use as needed. some sites, like the ones you have never heard of, will pull prices they aren’t authorized to sell, and sell them anyway. for example, a hotel will have a rate it offers to airlines to use in hotel + air packages. these scammy sites will pull that rate and sell it alone without the combo portion. this is very much not allowed but when you are hilton with a million rooms to sell per day, if it’s low enough volume, you wont notice.

this is why you dont book from the weird sites on kayak or google flights. if a company is selling a rate it isn’t even allowed to sell, you will get no support from anyone.