Their web site is no longer working.
A couple of months ago, I tried to RMA a faulty PSU.
I got the RMA form submission ok (while days later, links to the RMA section did not work anymore).
I sent the PSU to the indicated address (Netherlands) and, aftwer a couple of weeks, the postal service returned my package. I tried to contact *all* the Hiper email addresses found in their "contact" page to no avail. I never rexeived any answer.
So, at the end I lost 50€ sending the package and I felt really stupid.
Beware: DO NOT buy anything from this company, since they are dead.