User Merge Keeps Getting Rejected

We recently changed our business name and email addresses. I already went through the process of confirming both domains and merging the majority of our users. I just tried to merge a user like I have done so many before but this one is getting rejected. Both email addresses are in our account. I made sure to remove any premium apps and assigned groups , yet I am still getting a rejected status from the upload. When I preview the upload it says it is ready, but it will not work once applied. It does not tell me why either. Any other ideas to get this user merged??