Mihailo: don't know why they are tight lipped about the rejection but perhaps you could readdress the persons who first granted the interview w/ a simple request for the next time you are interviewed by theirs or any other agency? As a professional courtesy, they should reply.
I would state that I appreciated their time and willingness to interview me in the first place and that given the rejection despite an overall good feeling that I was left w/ from the interview, I'd like to know where I tripped up. Maybe you seemed too friendly to the women who were interviewing you. This is a simple mistake and happens easily, even for a person who has a good mastery of the language.
Best of luck and more so the next time around!