I'm so sorry to hear about the issues with this, I'm sure it's confusing but I'm happy to help.
From the sounds of it, you're unable to properly finish the migration as it thinks that you're already migrated with your other account. If this is the case, I would suggest creating a new gmail account and using that to migrate.
Please let me know if you have any further questions.
Just wanted to jump in here to check to make sure that you saw our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.
Have a great day.
It looks like we haven't heard back from the OP so I'm going to go ahead and lock the thread. If you have any further questions or concerns, feel free to create a new thread.
Have a great day,