How can we verify zeex partnership with amazon, nike, xbox etc?
They don't have partnerships with the retailers they have partnerships with the gift card providers who will provide gift cards for these retailers/brands.
so there is an additional mediator there? Not direct purchase?
Basically its a chance for Gift card suppliers to sell their gift cards for crypto [ therefore entering another market] and for you the customer to purchase with crypto with no fiat or fees involved. So, for instance, Zeex's sister site Zeek will have there 450+ gift cards available on the app to buy with crypto.
You can see the app in action here
https://www.youtube.com/watch?v=uE8CNBhS8Hg