There is no tracking number on a check that the IRS mails to you. The IRS will not make a direct deposit to a foreign bank, so if you do not have a U.S. bank account, they will only mail a check to you. Even within the U.S. it could certainly take 7-10 business days for a check to arrive in the mail. You are in a foreign country, so the mail may take considerably longer. All you can do is continue to watch your own mailbox. Open all mail even if it looks like junk mail.