Or if you prefer, you can phone the International Taxpayer Service Call Center at the number listed in that same article. That office is in Philadelphia, and it's usually easier to get a live agent there than the regular IRS number. If you get an automated system, do not choose any option for "refund", or it may give you automated info. Listen to the options carefully.
NOTE: It is not a free call, so be mindful of phone charges if you are on hold.
