Hi and welcome to the site, Lesley. I'm very sorry to hear that you've hit a snag with your very first swap. Despite what you might believe if you read through the forums, such problems are thankfully very rare in terms of the total number of swaps done every day, and of the problems that do crop up, most are usually resolved in the end. Hopefully that will be the case with yours.
The first thing you should do is email the other swapper - if you click on the More Details link by your swap, you'll see their details including their email address. Just put in a friendly email asking if everything's ok as you've not got your book yet etc etc. Hopefully you'll get a helpful response, but if not then you should contact support as detailed under the "I'm having problems with this swap" link. A gentle nudge from them can work wonders, but hopefully you'll get it sorted out long before that point!
Good luck, and here's hoping all your future swaps are snag-free!