There was crash of stats server. No coins were lost, only stats are broken. Hover your mouse over graph to see date and time of stats and you will see that stats are simply "missing".
Thanks for your reply. Yes, I understand that the stats are missing, and I noticed that by hovering the mouse. But before the crash I had 0.00581553 BTC unpaid balance and after the crash 0.00164576 BTC. So 0.00416977 BTC went somewhere, but it didn't get paid to me (as can be seen from the payment list and the black line).