Actually, K2 is one if the most actively developed extensions in the Joomla! community. There is of course a separate bug tracker for that, but all bugs reported in the forums are monitored. Of course, most of the times, they're not real bugs but they are just generic Joomla! usage issues, which some users believe are K2 related (they aren't obviously).
Lastly, if you are making money off K2, then consider hiring some of the companies listed in the forum to help you out, or just post your project in the related forum board on getk2.org/community. Don't expect that the K2 dev team will solve project specific issues you might have, neither will any other open source project.
We have taken note of the lack of documentation and re-worked the component to contain much more documentation and instruction.
We have also changed the way letters/rules and friending work to be more of a step by step procedure so that it's easier to follow.
If you ever have any questions or need hands on help you can call us directly at 971-832-9327 or email us at firstname.lastname@example.org
Please note that we do keep standard business hours so angry emails about a lack of response on the weekend or late night are really unfair. We do offer Urgent methods for contact under our contact list for true emergencies..