You could have deleted contact or it could be going to junk mail. If you had a computer problem around that time and mail bounced back they could have dropped you from list. Sign up again.
I also use www.e.harpercollins.com and www.bookbub.com to get info on low cost and free books for my paperwhite. You fill out info on genres you like and they send an email with possible titles. Will also work for other ereaders.