(no subject)

I bought a dress on ebay, and the postage was £5.65, which was pretty steep, but it was at least first class. However, when it arrived (a few days late), it had been posted 2nd class for £2.60. So I emailed the seller, I thought pretty politely, and said that this wasn't what I'd paid for, and would she consider refunding the £3 to me. She wrote back crossly, saying the actual difference in postage was only 40p, she'd spent at least £2 on petrol *and time* to get to the post office, and she couldn't believe I was quibbling about postage costs when I'd bought a dress for 99p, and she'd only refund me 40p by cheque if I sent an SAE (I paid by paypal). So. I am, in turn, cross about that. My options are 1) leave it and just walk away (the grown-up option) 2) go back to her and insist on a refund via paypal 3) refer it to ebay. (I might have done the last bit by accident - I wanted some advice, but they made me enter the item number and then didn't give me a chance to write a message before saying they were dealing with it.) Anyway. Any advice? It has become a Principle Of The Thing matter, but I mostly disliked her manner. It's possible I am being unreasonable, if so do say. When I sell I only charge about £3.20 for postage, and refund anything over £1 to the seller if it costs less.