I have have the same issue. Luckily I got a girl at 4200, but I missed 4000ryos and 500affection its sad... The problem was that I started event without restarting app, and it was buggy, so after I restarted it I was already past 1400 and I havent received any reward. On reaching 2100 i got first reward, on 2800 i got 2nd, on 3500 i got 3rd, and on 4200 got the girl!
It would be great if I receive 4th and 5th reward as well;)