When I ordered the book, I got two emails in response title “Your order from Eastgate XX” where XX was the order number. This is essentially the invoice.
The second emailed was titled “The Tinderbox Way (Third Edition)” and this one was the one with the download web links; three in fact for PDF, epub, and a DMG with both.
You might want to check your junk spam filter or trash incase it got filtered out or you deleted it by mistake. A lot of small companies use separate invoice/download emails, often due to the sales back-end of the process. IOW, if you get an email with just the invoice watch for a separate message with download links and licence keys (the latter item not needed in this case).