What time this morning? I’ve just checked and the data on the website at 7am this morning said it was active, so TfL/Serco are being naughty if it wasn’t.
I had to write into them previously because they closed numerous docks over the jubilee weekend (especially along southbank) with no warning on the website, and they still listed them as having bikes in them on the official app/website map!!
In answer to your question they do indeed have a status page for docks – although it is more for planned closures rather than faults: http://www.tfl.gov.uk/roadusers/cycling/18088.aspx