How to prove that someone is in a show but uncredited?

In the season 2 finale of Hazbin Hotel, "Curtain Call", Daphne Rubin-Vega voices Carmilla Carmine but isn't credited at the end of the episode. I've tried using a screenshot from the season 2 soundtrack as evidence, since she's listed as one of the performers on "Hear My Hope", but it was rejected.

I've had some other issues with the episode cast this season of Hazbin, but this one with Carmilla really bothers me since the soundtrack listing proves she's in the episode.

Any advice?