PBE Signups

Recently I've noticed that Riot has been encouraging all players to signup for the PBE due to the season almost at its end. They also happened to mention that the positive players get dibs on pbe access. I find it to be unfair that I've been signed for the pbe for a good while now and haven't received an acceptance. I as a player have been showing positive attitude, playing games to the fullest, and have been having fun while I play. However, their are some moments when i may be negative to another player for making a wrong choice in a game but I've never really been a toxic player overall. So my question is why hasn't my pbe signup been denied or accepted and Can anyone relate?