They have completely stopped communicating.
It looks like this is really a theft of $11,000. Yeah)
Does anyone have the ability to find out information about the owner of the domain name of this exchanger?
Regret to hear they stopped communicating with you regarding this issue. On behalf of the Bitcointalk community, I and my other colleagues try our maximum to support you. Unfortunately we regret when we see their nonsense reply. We raised a red flag against that exchange and left negative feedback as well. It seems they aren't concerned about the forum's reputation; hence, they aren't complying with our community. Personally I am still trying to help you but am not sure it does work.
I am communicating with BestChange by email and they said that they have not received feedback from the exchanger for as long as I have.
They are good guys, because despite the fact that they are a third party, they are interested in supporting users and helping in difficult situations as much as it depends on them.
Though they don't support through the forum,I have written to them personally about your issues. They mainly support through the mail; previously they solved one of the similar issues from another exchange. So I will advise keeping communication with Best_Change; they are supportive enough. Hope they could resolve the issues.