Advice on Paddys!!!

I am sooooo upset;

I finally decided to order the Long paddy Satchel from diabro.net and submitted the order. They payment went through ok with Paypal and I got a confirmation e-mail.

Today their customer service e-mails me saying they just sold out of the bag yesterday and they don't have one for me and cancelled my order. They refunded me right away.

I am soooo upset becuase why would their website do that, how could the transaction be completed when there is none in stock. Second they took payment which I had to pay a service fee on to the credit card company and I'll have to pay again for the refund.