I actually contacted slacker (via Twitter) and Tesla support (via email). Slacker told me it was a problem with the account on the Tesla side. Tesla told me to press the "Restore" button in the 17" settings to reset the account. I was skeptical that would work as some other stations were working but pressing restore immediately (they said it could take up to 24 hours) fixed all my slacker stations (specifically country ones). It broke on the 7.0 update, pressing restore fixed it (so far permanently).