What in the world is going on with the 'Purchase not authorized' situation?

Three weeks after receiving the new book, the buyer decided that the 'purchase was not authorized.' Of course, amazon automatically approved the return, including return postage. I know they are trying to bankrupt the small sellers, but I do not offer try it before you buy it on anything, including books.

Do sellers have ANY recourse to this idiotic new policy besides just choosing to sell elsewhere?

I have had two instances in 2 weeks where media mail wasn't offered for a book because it said that it couldn't be delivered in the timeframe chosen. I don't know that I ever chose a time for delivery. I had to go to the post office to buy media mail (the mailman usually picks up off my front porch). How do you change the delivery time?

I am a merchant fulfilled-only bookseller. I was just charged $25.00 extra for a book returned to me based on a discrepancy with stated packaging dimensions. I was originally automatically charged $6.00 for a 1-pound shipping envelope sent via USPS media mail. I buy my postage independently through Stamps.com and ONLY ship via USPS. This sound like a UPS issue. The USPS does not do things like this, especially to a merchant-only seller. This is an obvious mistake on Amazon's part; I just opened a case. This has never happened before and I've been selling for a very long time. Has anyone else experienced this problem?