If you are the creator of these items you will be listed as such. If the only reason you gave them to him was for him to place them in vendors while you were in business together you have a legitimate claim since that business no longer exists.
Do you have logs of conversations you had with him where you discussed the use of these items? Do you have a partnership contract?
Even if you do not I would suggest sending him a cease and desist in a NC notifying him that he must stop selling your items immediately and warn him that if he does not you will file a complaint against him with LL. Be sure so document that you sent it to him (transaction records) and log any responses; you can use them if you do have to file a complaint.