http://www.xtrememiners.net/#!products/cngp
They have contact information:
http://www.xtrememiners.net/#!impressum/cvj3
Impressum
Owner: Mr Berg.
Adress: Eschersheimer Landstraße 19-21
60322 Frankfurt am Main, Germany
Finance Office: Frankfurt am Main IV
Phone: +49 152 169 418 29
Who easy to verify it?
"Mr Berg" doesn't sound great for a start. But even so, they may have an address, but unless they let you in to inspect their premises, you aren't really learning anything at all.