It its as Castleman wrote in his posting: Normally this coins are delivered in a small plastic bag with a paper slip that shows the activation code. So I think, the guy who sold the coin to you should have the code. I don't think the shop will be of any help.
Some years ago I had lost the activation codes on one of my coins. I send an e-mail to Groundspeak and asked for the code. They were very helpful then.
I have a similar page...you can find the names of most icons here. The ones with the * I have not seen on anyone's profile, so I the name might vary from what I have listed. It is complete as of last week.
Geocaching Icons
Nr. 423 will be "Geocaching - All In One Geocoin"