I bought this specifically to use 2 external monitors with my 2012 Macbook Air, one with DVI, the other with VGA. However, when a DVI connection is made, the VGA monitor goes black. I've been playing around with a bunch of display settings but can't seem to find a way to use my 2 external monitors. I also did not find any live chat/support/help on the website other than a Hong Kong phone number. The product is promised the ability to add multiple external monitors.