I had a good experience when I contacted them. It was several years ago.When I have needed help with ChessBase products, the first thing I do is look for answers in the series of articles by Steve Lopez. However, those explain how to use certain features, not what to do when there are technical glitches in the performance of the software.
I recently had the need of the same i.e. Chessbase 10 SP6.
Chessbase Support pointed me to
Posted with Chessbase Support permission.
I can confirm that the link is correct, it downloads the SP6 update, dated December 19, 2011 (in "Help" - "About..." in Chessbase 10). To my knowledge, this is the latest update. (See also this link: http://www.chesspub.com/cgi-bin/chess/YaBB.pl?num=1262419088/30#42)
I noted today that (un-activated) Chessbase 10 is 'timing out' after about 90 seconds, with the message "The serial number is not valid". After clicking "OK" to close the info window, the entire program shuts down after about a minute. This does not occur if the program has been activated.