Ever since December 1st, AdSense publishers who needed to verify their accounts via phone were unable to, due to a bug.
Google announced on Friday that they have resolved the issue and if you have yet to verify, you can now do so. Once you verify, you may need to remove any holds on your payments. To do so go to your "Payment History" page and look for a 'Required Actions' box at the top of the page.
Forum discussion at WebmasterWorld and Google Groups.
