I'd just send an email to them and say something along the line of: I am very happy with my seeds and all the bonus seeds but I seem to be missing a package of XYZ. Since they are one of the packs that I really really wanted, would you mind checking to see if they got left out of my shippment??
I sold seeds last year and each auction listing was for multiple packs of seeds. I checked, rechecked and checked again but I still got confused sometimes, so it's a very easy thing to do. Those little packs can slip out of your hand very easily. I can not imagine anyone getting upset over you asking for the seeds that you puchased.
Now, there's always the possibility that your pack of XYZ got put into the wrong envelop. If this happens to be the case, the seller may not have another pack of XYZ to send you. In this case, they'll probably offer a substitute or refund. THis is another thing that can happen really easily.
Hope this helps you, Mona
