This is very strange. My Last payment is posted to the site but I haven't received it. Block explorer also shows "No such transaction" when I click on provided link in payment history. There seems to be a glitch in the system.
Have you read the help page that is shown after pressing the Instant Payment button ?
Or it was auto payment ? Don't worry, there are no glitches in payment system, it will reach you.
Hmm, I should invent a way to somehow show help page after autopayments too

I have been using the manual payment for weeks and every time it shows up within seconds. This time took about 25 minutes for some reason (both in block explorer and my wallet). It ended up showing up though so I am good. Thanks for quick reply.