Deleting Credits

I am trying to delete some credits off my page that are no longer relevant. I have tried submitting these deletion corrections through the imdb website countless times and always get a response that tells me there is not sufficient evidence to delete. But I am never told what information I need to provide. I've tried reaching out to imdb multiple times and have had no luck getting in touch with someone who can help me. Does anyone have any experience with deleting credits they no longer want on their page? Any guidance would be much appreciated. Thanks in advance!