This description said to post questions about the marketplace here.
What's the general barrier to payment? Is there a certain amount of time before I just void the sale? I'm waiting on payment for the buyer and haven't received anything despite two or three geekmessages.
Yes, you should typically decide what your time from confirmation of sale to payment should be, then make sure its in the listing, so the communication and expectations are clear. If they don't pay within that time frame, cancel and relist. What that time frame is depends on you. Personally, I use three days.