Hi Matthew,
Thanks for writing us about this, and I'm sorry the discount didn't work for you. I took a look, and the discount should work with the two books you purchased (the only exclusion is books published by Wrox/Wiley), so I'm not sure what went wrong. Please let me know what the other two ebooks that you would like are, and I'll add them to your account.
If you run into issues with any future orders, you'll usually get the best help by contacting customer service at orders@oreilly.com or 1-800-998-9938 / 707-827-7000.
Kind Regards,
Rachel James
O'Reilly Media