You can withdraw your offer or counter-offer as long as it hasn’t been accepted by the seller. To do this:
go to Menu > My offers > Placed to access all your offers.
click on the relevant offer/counter-offer, then on the 'Withdraw offer' button.
Once you’ve withdrawn an offer or counter-offer, the seller can't accept it anymore.
You cannot withdraw an offer that has already been accepted. Once the offer is accepted, the items are marked as "sold" and placed in your cart for up to 24 hours, waiting for your payment. If you have not completed your payment within 24h, the offer will expire and the items put back for sale.