You sir are a moron. Read the rules of the site. Amazon does allow up to 21 days for delivery for Marketplace sellers, Amazon DOES handle the refunds, and it is more than reasonable to suggest that there is a possibility that the book has been lost by USPS.
What is unlikely is:
Your claim to him being fraudulent based on a change to a phone number. Assuming that this seller that has a successful business on Amazon.com would be trying to scam you out of a $6 book. If this is something that was needed for work, as soon as a problem seemed to have arrived, I would have spent that almost nothing you spent in the first place to get another, or gotten it locally and handled this situation with communication or a claim. With my priorities in line, I'd at least have secured the book from another source.
You assumed the seller was able to provide you with confirmation of a refund, since they can obviously give you a tracking number (By way of creating a shipment and paying for the tag). Never mind the fact that the seller has nothing to do with the merchant account Amazon uses to process these payments, the seller has no access to the "confirmation" number.
The seller is also held to strict guidelines put in place by Amazon which would identify the types of seller you claim this party to be. If they were the type of seller you claim, they would have been banned and it is impossible for a seller to get back on the site.
You're a sketchy buyer, I wish amazon would allow us to block some buyers. I'm willing to bet you didn't even give the seller ample time to respond. I'm sure you found out about it possibly being lost in communication from seller on an A to Z.