Let's make it more interesting...You take your car in for service, to have something taken care of...and the repair facility does a sub-standard job. I.e. saying the replaced your transmission when all they really did was replace the valve body and change the fluid. In Michigan that is a CRIMINAL case...because you asked for a service and they told you that service was done even when it in fact wasn't.

Where is the difference with your problem...You asked for Premium, and they gave you regular...and then told you it was premium.

Auto facilities are mandated by the NHTSA to do work and perform services to a "MANUFACTURER MINIMUM"...meaning that they cannot provide a service that is below what the manufacturer did.

I once got a repair place in trouble because I needed some valve work...they told me it would be a 2 angle valve job, and a "Premium" 3 angle valve job would cost extra. They even put it in writing for me...