Can't find anything of your past on google, bing, yahoo, qq, etc... The domain, username even Skype. Don't have any proof to show that these keys are legit.
Steam games not bought form steam > retail codes but haven't seen any codes cheaper then half price of steam price.
Uplay not form uplay ? > uplay revoke-ban many accounts bought keys form the market like g2a
Origin > no idea.