Ive never had this issue because I use PayPal and they wont release IP addresses to me. However since you have this information handy id use it for your benifit. E-Mail the person or call them for verifications to see what is happening. If you dont want to spend the dime then dont send it out or atleast get really insured and signed for in many ways incase something does go down.
Why not just call the customer and tell them your situation.. I am sure every genuine customer will understand.. and just ask him to place the order on the phone. (if possible you should dial the number... so you know where you are dialing)