Key Frags never drop?

People have told me that it takes a month to reset, but it's been 2 months, and I have gotten 0 key fragments. I've gotten absurd amounts of S and S+ ratings, and I've gotten 0 key fragments. I'm not sure if this is intentional, but personally I think that my game is glitched or something. 2 months and no key frags is crap.