Look in Users and see if Migration Assistant transferred them to a new account. The problem with migration is if it isn't done the first time you boot your new mac/new system, it will create a new user. I wish this this was better documented by Apple.
Migration Assistant is meant to be run the first time you boot your new Mac in Setup Assistant. I really wish Apple would be clearer about this. If you decide to migrate after that it will create a second account. Look in Users and see if Migration Assistant transferred them to a new account.
If so, you have 2 choices.
1. A full erase and re-install from yourRecovery Volume via Internet Recovery, then run Migration Assistant while in Setup Assistant.
2. Try to consolodate the accounts by putting files in Users/Shared and then moving them into your main account. Here is a good list of items and where they belong.
http://pondini.org/TM/28.html
If it were my Mac, I'd re-install and start fresh.