what is the 18 digit number of your submission attempt? What was IMDb's response in https://contribute.imdb.com/contributions/history (view details)? If it a lack of evidence (rather likely), you could post a screen grab here testifying your submission.
Can you clarify if you are having trouble submitting the credit, or if you have submitted the credit but it hasn't been approved? If the latter, please provide the information Vincent requested above regarding your submission.