Easy fix:
1: make 2 sites, a clean non adult that attract women and a standard that get the men to join
2: insert filters so when men send pictures of their cocks, a picture of a cool business man arrive. Important is to remember to switch profile pictures as well
3: when women is sending their replies then instead of a 60 year old mamma you insert nude model pictures
4: for more advanced stuff you do auto search and replace filtering of the messages they exchange.
The downfall may be that if they meet the man will think he is about to get laid by a 20 year old hottie in the backseat of his pickup truck and the old mamma think she met a 30 year old stockbroker and is about to get a romantic dinner in the best restaurant in the city.
The good part is that at that time they have already referred 3 other friends.
The fix: offer them 50% discount doing an instant upgrade, they have seen it works, they where just unlucky
Disclaimer: This could for some be considered bad business practice and possible against multiple marketing laws