If it's like last time, the limit for wanted and instance are shared, which means you can get AT MOST 11 keys per day (get an odd number from instance first, do wanted, at 9 you will gain +2 for 11)
At the same time, if you met the quota due to wanted, it won't matter if you spent 3953285920 stamina, you are not getting anymore because you are capped. I would hazard to guess that this is what happened to you.