How Could I Lose a Box of Day-Timers?

My records showed that I bought a Day-Timer refill set last April (starting July 2010). Today I went to install the July 2010 book and discovered that I seem to have lost the entire refill set. That's annoying. It's not where I thought it should be, and it will cost me about $30 to buy another set; besides, I'll be without my Day-Timer for the first week of July while I wait for it, because it's not sufficiently urgent to spend more than the cost of the product on express shipping.

Yes, I'm old-fashioned and still use a paper Day-Timer, not an electronic equivalent. I do hope that I didn't put it into storage, thinking it was an older year rather than the new one. I hate wasting resources like that.

Update, Friday 14:00: See this post for a story of astonishingly good proactive customer service from Day-Timer to help me make good my mistake.