Adding Cast

We've tried to add Cast repeatedly and some are added while others are not. Mostly it's the ones with lower IMDB rankings but this definitely hinders us moving forward in many ways. I even added the LOI granting permission to be added to IMDB from one cast member and it still says pending! IMDB didn't use to be this difficult. Any suggestions on how to add cast members promptly, no matter their IMDB ranking? We've been battling this for weeks.