Unable to edit one of the contacts in specific supplier

Summary:

Content (please ensure you mask any confidential information):

We were removing one of the contacts one of the suppliers which had a supplier user account already created. By mistake the email ID was removed and the contact was saved in the supplier master. Now, we are unable to delete the supplier user ID for this contact. Neither that we can make any changes in this supplier contact. Any pointers on getting this particular contact and corresponding supplier user ID deleted from the system.

Version (include the version you are using, if applicable):

25D

Code Snippet (add any code snippets that support your topic, if applicable):