The first thing that comes to mind is… have you been sending invoices or payment reminders? If so, every time that you do, the 4-day timeframe is reset to zero so you’d need to wait another four days (each time). If that’s the case, just wait and don’t send another invoice/reminder, and the option to cancel with the nonpayment reason should appear after the next cycle of 4 days.
The second thing that comes to mind is … glitch of some sort. If that’s the case, you should contact Live Chat during business hours and explain, and ask if they can cancel the transaction with the reason “buyer didn’t pay”.
