I have submitted my photos to my photobook more than 30 days ago, and I have not received my photobook.

When you submitted your order, you should have received an Order Confirmation email from photobooks@kensington.com which contains an Order ID (check your Spam folder just in case)
A few days after that, you should also receive another email from the same email address with a DHL tracking code for your package
Please have this information handy then write to inquiries@clientprograms.kensingtontours.com