Thanks for reaching out for assistance. Please note; the Zombies ranking system differs from that of Multiplayer as it is not a linear ranking system. Please review the following support article regarding Zombies ranking. Perhaps it can shed some light.
https://support.activision.com/articles/en_US/FAQ/Zombie-Leaderboards-FAQ/?q=Cle aring+the+Xbox+360+System+Cache+or+PlayStation+3+Game+Data&l=en_US&c=Game_Title% 3ACall_of_Duty_Black_Ops_II&fs=RelatedArticle
Glad to hear deleting the Title Update worked for you.
@JoshVelvet, Please try it as well to see if it helps.
Also, let us know the platform you are on if the same issue still occurs.