yeah, hate to say it but it is your own fault. You have to keep up with domain re-registering. Most decent registering services will send you a notice.
I have been with
www.123cheapdomains.com for over 3 years now. They send a notice at 90,60,30,5,1 days before it expires, then they hold it for an additional 30 days i believe in case you just somehow missed it so you can still reregister it, although after it expires i think it cost a little more.