After you set up an account, you should have received a response from email@example.com. It contains a link to itunes connect. Itunes connect is where you enter your banking and tax info as well as manage all ibooks info. There's a link to the irs website for you to obtain your tax i.d. It only takes a few minutes to do that.
Just noticed when looking in iTunes Connect that Apple does have a support email and phone number for questions.
iBookstore email support is available worldwide to assist you with your questions or feedback. Hours of operation are 7 a.m. to 5 p.m. PT, Monday through Friday.
We respond to most Contact Us inquiries within 3 business days.
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For immediate assistance, call iBookstore support at 877-206-2092 (toll-free). Speak directly with a support representative to have your question answered as quickly as possible. Hours of operation are 7 a.m. to 5 p.m. PT, Monday through Friday.