Change of ISBN information not successful

This is the case of a joint publication. I submitted a resource on behalf of my organization with the ISBN from the other entity, which makes it impossible for them to register the resource on their side because their ISBN is already assigned. I resubmitted using our ISBN and got a “successfully updated” message. However, the other organization is still getting the error message that the ISBN is already assigned, and thier ISBN is still showing on our submission in spite of the change. This still makes it impossible to register the resource on their side. How do we resolve this situation?