Annoyed and wondering what I can do?

[Lesbanian]

Bought a dress in Ebay ages ago for a party this Friday, arrived last week and doesn't fit :(

Spotted another one to buy on Sunday, checked measurements properly this time. Was worried it would not arrive in time but saw on the postage options you could choose free second class delivery or pay extra for first class recorded, great!

Emailed the seller explaining in a rush so paying for first class, bought and paid leaving a note also pointing out i had paid for first class.

Got a message Monday to say the dress had been posted. I replied asking for a tracking number (my post man has a habit of not leaving cards meaning they sit at the depot for ages) and got told there isn't one.

Seems the seller sent standard second class :(
Dress is not yet here, it may not arrive in time so if it's not here tomorrow I will have to go out and get a replacement.

What can I do seeing as
A) I paid extra for first class recorded and was not given it.
B) If the dress does not arrive tomorrow it is useless to me and I will no longer want it ( I purposely choose a seller who had first class recorded listed).

refuse the delivery and ask royal mail to return to sender then either ask for a refund or open a not received dispute to get your money refunded I reckon?

With a not as described case won't I need to prove sending it back, which I can't do if I refuse it.

If it arrives tomorrow I do want it but then do I have any way of getting the £6 I paid for first class recorded refunded?

but it won't be not as described if it isn't delivered will it. Just refuse the delivery - it will be returned to sender and then you can file a not received case. And you will get a full refund of everything you paid.

Ok will do that thanks