Replying to A little issue (legal rights)

Last season my local mountain purchased a photo from me for use in their mountain guide. The invoice I wrote them regarding it specifically stated that it was for use in the '10/'11 season mountain guide and any further use would require more negotiation.

I was told today that a cropped version of the photo was printed in this years '11/'12 season mountain guide. I need to talk to the mountain to get some sort compensation. I was hoping something with experience with this sort of thing could offer me advice on how to proceed.

Thanks M/A