Need to remove my name from S.T.A.L.K.E.R. 2 cast list

I have formally requested to have my name removed from the S.T.A.L.K.E.R. 2 cast listing, as my credited work pertains only to an unreleased additional segment of the game. I submitted my contract with the game’s producer along with screenshot evidence of my email correspondence with the production team to IMDb.

However, IMDb has declined my request, stating:“More Evidence is Required. Your contribution has been declined. We have been unable to verify your contribution. Unfortunately, we were unable to accept your submission as we could not verify the information provided.”

For transparency, I had previously added myself to the cast listing. I am left wondering - what additional evidence is needed beyond what has already been provided?