Bad situtation for sure but I assure you there is nothing that can be done criminally. It is 100% a civil issue.
Theft; receiving stolen property
Sec. 2. (a) A person who knowingly or intentionally exerts unauthorized control over property of another person, with intent to deprive the other person of any part of its value or use, commits theft, a Class D felony.
IC 35-43-4-3
Conversion
Sec. 3. (a) A person who knowingly or intentionally exerts unauthorized control over property of another person commits criminal conversion, a Class A misdemeanor.
( The offense under subsection (a) is a Class D felony if committed by a person who exerts unauthorized control over the motor vehicle of another person with the intent to use the motor vehicle to assist the person in the commission of a crime
For any crime you need actus reus and mens rea....Criminal state of mind, and guilty act. If someone ships you product by mistake there is no criminal intent there and really no guilty act. You could consider him not shipping the product back a guilty act but you need both not one or the other.
Your going to have to take the time to sue him civil court. He will definitley lose. Looks like he has a ebay business. Its so easy to make an ebay account these days. You can even bid on items as a guest. Would be a shame if a bunch of people got together and basically shut down his ebay business.