craftgrrl | an etsy sale - what would you do? not sure if i should complete the order..

hello my fellow craftgrrls, i need a little bit of advice regarding an etsy sale..

i'm not sure if i should complete the order:

i just recently received an e-mail from etsy that one of my photography books has sold. i made 10 of them (not for my online store, but i was selling these to make some extra cash as an artist to fund my photography classes). anyway, someone purchased one, and i am simply awaiting the payment.

then i noticed the shipping address included not just their name, but also "u*space gallery" and i checked out the website that was associated with the buyer's email address:
http://www.uspacegallery.com

seems to be a store that sells limited edition art. my book was labeled as a limited edition because i made only ten of them, with one to be displayed at the student art show (and sold at the show, for personal collections, but it didn't sell). i also included information that it was a 'big' project i worked on, because i handmade/handbound ten of these books. i was selling all but the original #1 (my own copy) + two copies that i gave as gifts.

anyway, i am not sure now if the etsy buyer is attempting to purchase my book to re-sell in their art store.. and i don't know if i feel comfortable with this. i was selling these books for people who wanted to own one for their own personal collection. i already e-mailed the buyer saying i would ship it as soon as payment was received, but should i send another e-mail asking what their intention is with the purchase of this book - and that i may have to cancel their order if it is for resale?

i don't feel comfortable with the 'what if' thought that someone might purchase my book, then re-sell it for more money and profit off of my artwork, with myself only receiving the asking price i listed it on at etsy. :\

what would you do?

ETA: I e-mailed the buyer to see what their intent was (personal or resale), and they replied, stating their intent was to resell the item in their store. Anyway, what's done is done; they just need to send payment and I just need to ship it. I wrote up a contract (need your opinion if it needs anything else or anything needs to be removed), and am just wondering if I should bother with including it with the item or just forget about it:

Agreement to Sell Works of Art

The artist, **my name**, will supply the buyer, **buyer's name**, with the following item for re-sale in the U*Space Gallery, under the agreement that this item is not to be copied, reproduced, or replicated, and that no derivative works are to be based upon this item.

Item to be sold:
• “Open Shutter” Photography Book, Spring 2005, Limited Edition, No. 5

Artist's signature and date

Buyer's signature and date

Thanks so much for the help & advice, everyone! I'm actually really excited about this now because I finally got an e-mail response that wasn't under 10 words, and they are excited to carry my book in the gallery. :)