I had a similar experience a few years ago. The Independent was giving a 'speak Italian' CD away with their Saturday issue, and the accompanying book with Sunday's. I got the CD all right but could I hell find a copy on the Sunday. I went in my car scouring the entire area but with no luck, so it was ciao to my attempts at learning a new language.
you will usually find that they were not delivered to the whole area, if one shop does not have neither will the shop around the corner, only way to get one would probably be a big supermarket like Tesco or drive out to the next town/village, it has happened to me, now I check before leaving the shop.
It's happened to me a few times. I once bought the Sunday Times only to find when I got home that the section with the crosswords was missing. That's al I really buy the paper for so that was £2 down the drain. On another occasion I found that the cellophane wrapping had been torn open and a free CD removed. I always check through now before buying, no matter how many funny looks I get.