As the others have said, there is a 30 day hold on funds being paid to the seller if the seller is new or has not sold on a regular basis recently.

You have to be properly signed up to managed payments too so that ebay can pay you at the end of that 30 day period.

Importantly though, you cannot just hold onto your item till you get the payment into your bank account. As soon as the buyer has paid ebay, you are expected to post off the item asap.

Your item needs to reach the buyer by the estimated dates that were in the ad.