Yup... having similar problems here. I've been trying to get a warranty replacement headphone set, but no response to emails since Aug 1, their 888-number only comes up busy, and the 714- number in California is answered by an autoattendant - trying 200 for tech support, 201 for sales, or 202 for all other inquiries results in being transferred to a voicemail box that is full and not taking messages.
As of today (8/14) their us website is totally down (mobibluamerica.com) - but the Korean site is still up.
Not good ... I bought from Amazon so let's see how much help they will be (they are still selling these!). I may just end up trying to return the whole damn thing and let Amazon, Amex, and whatever is left of this company duke it out.