As far as I can tell, there’s nothing wrong with that. Charging $1500 for it, on the other hand, is a crock of shit. It’s designers like this that give us all a bad name.
Is there a contract? Does the contract say a custom design?
Do not pay this person $1500 for a theme he did not create. If you can provide some more information on the project I would gladly help you bury this person into the ground.