Request for a Credit

I've submitted several pieces of evidence to confirm my most recent request for a credit in the form of screenshots of the following emails: from my agent that includes the offer, role, show, and role; from the production company providing me with a copy of the script for the episode in which I was cast; from the production coordinator that includes a work packet that I must complete and return to work on the episode in which I was cast. While I'm confident that I'll eventually receive credit, I'm wondering aloud why what I provided did not suffice and resulted in three consecutive declines.