Once a buyer has paid and whether the money is in paypal or held because you are a new seller, you must post. Buyers cannot cancel a payment once made.
Failure to post once paid will only give you problems with bad feedback, late deliveries which count against you in your records and cases being opened for Not Received.
If you use the seller hub, it couldn't be easier, all sales are split up into Sold, Awaiting Payment. Paid Awaiting Dispatch and Dispatched. Using these as a guide you will NEVER dispatch unless paid.
If not paid after 2 days you can open an Unpaid Case.
