Hey buddy, first of all calm down. Secondly. Did you refund his money? If so then no you're not a scammer and he should publicly admit that. If you haven't, then yes you can be classified as a scammer as with any other shop that does what I read in your emails. It's not hard to figure out.

Now you said something that is interesting. You mentioned Switzerland trade laws. You must not be aware of this https://econsumer.gov/#crnt
Which Switzerland is a part of. And yes I did see the case number for his complaint with them also.

Now as far as if your actions are criminal here is this.

Q: How does the IC3 define Internet crime?
Internet crime includes any illegal activity involving one or more components of the Internet, such as websites, chat rooms, and/or email. Internet crime involves the use of the Internet to communicate false or fraudulent representations to consumers. These crimes may include, but are not limited to, advance-fee schemes, non-delivery of goods or services, computer hacking, or employment/business opportunity schemes.
https://www.ic3.gov/faq/default.aspx

Now I haven't talked to him in a few days, so if you have resolved this I am sorry and will retract my statement, but if not. Pay the man his money. After all, you owe him he doesn't owe you!