http://www.markersrus.com/ is still alive... thats one of their sites I believe... but it won't do any good if they aren't there.
In terms of the A5, either take it up with Tippmann, or post on the forums and try and fix it yourself. It sounds like Havoc have gone down... but keep trying they may be on holiday or something
Word on the grapevine is Havoc have shut up shop for good. Credit card companies are now chasing them as they apparently were still taking orders after going bust.