There is a support page on the blackmagic site, as well as the forums over there.
The support page does offer email and a phone option...depending on your location. I've email'd them about a couple of licensing issues, and they were pretty good to respond. Not sure how well it works for a "how do I add a keyframe to a ..." type of question.
The forum is not blackmagic support as such, but they do chime in, plus as with the cow, there are plenty of others to help out.