How do I go about filing a claim in conciliation court with someone who purchased an item out of state and hasn''t paid for it?

I sold 6 iphones on ebay in one auction for $3000. Buyer was not happy with the phones and filed "Not as described" claim through a chargeback with his CC and won the case. During the case, the buyer agreed to sending the phones back, granted he won the case, and received his refund. Upon receiving his refund, but refuses to communicate, and is not following through with the return as promised. I need to get my merchandise back, but I have no idea how to pursue this case in conciliation court, as I live in MN and he lives in IL. Also I did the eBay sale through my roommates eBay account (we buy and sell stuff together), and the case is under his name, but I am the one who has their money stuck. Is this going to be a problem? He is more then willing to help with this case as needed. Please recommend how I should pursue this via courts. Thanks