After listening to this podcast for adding or removing delegate in Gmail, you can manually add or remove a delegate in your Gmail account. If there you are facing any issues or problems like, There's a delegate that I didn't add, I can't add a delegate, I have a delegate and locked my account, The link to access your delegated account is not valid etc. You can contact Gmail Customer Service to resolve the issue.

https://www.emailhelpdesk.us/support-for-gmail.html