With 2889 referrals, I find it odd that I've never gotten a 50% commission from a 0.22500000 BTC payout (10000 lucky number).
You are not the only one (though your referrals number is really astonishing, lol)...
He has his own service (won't advertise it here since he prohibits advertising/saying anything about but his own in his thread and this thread is surely not his, so fair play, lol), and when I used it, I had often seen a freebitco.in ad there, so it is a no-brainer he got that many referrals (when you give it a second thought)...