Hi,
Yesterday we had the same problem with my wife; it was disappointing.
The only way to fix this issue is to create another new GCKey account with a different user but the same email as the old one. Once inside the new account, you have to find one link that allows you to link applications from another account; having the information of the previous application, you should be able to import it to your new account.
It sounds nonsecure; however, to link previous applications, the system asked you to confirm much information about that prior application. If it's your application, you will be the only one with all that info; worst case scenario, you would have to go through your email or personal files.
For our case, we wanted to recover even previous approved applications; the most complex info to find was two specific numbers related in our permit documents.
I have decided to take some time and suggest our solution as we felt so bad yesterday after that error appeared. We don't want more people in that position.
Let me know if you have any questions about our process to address this situation.