Many sellers are now experiencing a few days delay in receiving payments, due to eBay's new managed payments system. This can legitimately cause a short delay in dispatch times.
New or returning sellers are different. Their payments are held as a security precaution for 21 days, or until they can provide postal tracking proof that they have delivered the item.
EBay/PayPal will tell the seller that their payment has been received, and they should now post the item. If they won't, they are refusing to follow eBay's rules.
You do NOT have to wait for their payment to clear, and should not accept a cancellation request unless you no longer want the item. If you still haven't received your item by the latest estimated delivery date, open a case under eBay's money back guarantee through the resolution centre. I'm afraid this is the only way that some sellers will learn.
