How to get rid of committed to buy on ebay?

Please don't be rude. I know i'm dumb, ANYWAY. I wanted some boots n i went to pay for them. I don't recall ever saying "COMMITING" to buy i just went to buy it now. I got my mom's card but it wouldnt go thru n she said she'd go to the bank n fix it the next day. However i saw another pair of nicer boots on amazon and bought those instead for cheaper, and no longer need the ones on ebay but i can't get rid of them, they are still there and want me to pay. Also i purchased an iphone on ebay Monday that i paid for and still hasn't shipped n i think it might be cuz i haven't paid for the boots, which i no longer need. Help? Thank you!

Added (1). Ps this was NOT a bid.

Offering to BUY It Now is a commitment to buy from you.

You are obliged to go through with the transaction, in the UK upon receiving the item as it was a distance buy you are entitled to return it at your cost for a full refund of the cost of the item, less shipping.

If you do not there's a risk that ebay will close your account.

If you contact the seller of the boots and tell them you no longer want them, they will cancel the transaction. No seller wants to send out an item that they know will be returned. If you do nothing they will file an 'unpaid item' claim 7 days after the purchase and this will be recorded against you. If you don't do this frequently this will not be a problem though.

On the iPhone purchase, the dispatch of this will not be related to the boots purchase unless you bought them from the same seller. Contact the seller and ask if it has left yet. They may have sent it but not updated the status on ebay.