Or the opposite! They are earning enough/have built a big fan base and not enough affiliation to be payed!
By the way, if I can give my 2 satoshi, always use "reputable" and well known site (in the past I used betfair.com affiliation...) and regarding betnomi yes currently it seems there are some issues and this is not the best moment to join their affiliation program.
To OP= how did you get so many registrations? Did you have a specific advertisement? Can you share with us?