Russell wasn't banned for missing tests. Here's a description of his offence:
"WADA rules state that athletes across all sports must inform their local anti-doping agencies where they will be for at least one hour each day to facilitate drug tests."
This is from the ASADA site:
"Violation of applicable requirements regarding athlete availability for out-of-competition testing...
...including failure to file required whereabouts information and missed tests which are declared based on rules which comply with the International Standard for Testing.
Any combination of three missed tests and/or filing failures within a twelve-month period as determined by Anti-Doping Organisations with jurisdiction over the athlete shall constitute an Anti-Doping Rule Violation.
Athletes who are part of the Registered Testing Pool (RTP) need to let us know where they are going to be, at specific times, so that we can perform no-advance notice testing. If athletes in the RTP do not provide current and accurate whereabouts information, they may incur a declaration and three declarations in 12 months may lead to an anti-doping rule violation."
He screwed up his paperwork. I guess when you're travelling the world playing cricket it would be easy enough to forget but doing it three times is pretty sloppy so he has to cop the punishment.