Usually any feedback appears within seconds.
Some PowerSellers as a perk of their status have a seven day Hold on feedback.
This means that no feedback, negative or positive can be left for seven days after the transaction.
Note that FB is not used by eBay as a measure of a member's account.
If you have a problem with a transaction you can open a Dispute in the Resolution Centre at the bottom of this page.
Problems can also be addressed through Paypal's Buyer Protection or the chargeback service of your credit card.
