User assigned to Commerce and cannot unassign

User assigned to Commerce and cannot unassign

I have a user that is no longer with us and I am trying to deactivate his account. The problem is when I try to unassign him from commerce I get an "Error Occurred!" message. And if I try to deactivate him I get another error message stating "Unable to deactivate user in Commerce."  How do I remove this user from commerce and deactivate him?