I agree that it's the buyer's problem if they don't know their size in a particular brand. I've bought tons of shoes off ebay that don't fit (Chanel, Dior etc) but I figure it's my problem and not the seller's (obviously)
I think it was very gracious of you to accept a return (minus your expenses) Personally I'm not a fan of sellers who charge restocking fees, it just makes them look like they're trying to make a quick buck rather than offering their customers their best service (sure, it might cost you time to relist the item, and time equals money, but by offering great service you might get repeat buyers which again will make you more money. In building a business, that would be the most profitable way of thinking. Now you're obviosuly not looking to build a business, but still )
I think it was very gracious of you to accept a return (minus your expenses) Personally I'm not a fan of sellers who charge restocking fees, it just makes them look like they're trying to make a quick buck rather than offering their customers their best service (sure, it might cost you time to relist the item, and time equals money, but by offering great service you might get repeat buyers which again will make you more money. In building a business, that would be the most profitable way of thinking. Now you're obviosuly not looking to build a business, but still )