Hi! It´s like a “second hand” web, where anyone can sell things, used or new. This seller is from Cordoba, no the Spanish one because he price things on dollars. So I guess he is from the Mexican city also called Cordoba, or maybe the Argentina one. (Confirmed after reading the questions to the vendor, he is from Argentina)
About the questions, you cant know if the kits where bought there, cause the people can say that they printed them. But the ugly thing is that they are making money with you design, and raping the license of the parts.
So yes, you should send they or him a message.
PS: Im from Spain, if you want me to “check” or traduce the messeage, if you are not sure of what are you saying, send it to me and I will correct the errors you might have.