After a routine oil change of a 1 yr old car. The engine was locked due to a lack of oil put back in. What are my options?

My 2008 cadillac CTS was taken to the dealership in which it was purchased to recieve a routine oil change. On the way home the car broke down. The dealership drove out to pick the car up late that evening. The next morning I recieved a call informing me that my engine was locked due to an employee neglecting to replace the oil that was drained. The dealership wants to replace the engine with one they found that has 1000 miles on it. Is this fair for me to accept? Is there something else I need to do in order to protect myself from future problems should they persist.