Try this definition:

http://www.outofthefog.net/CommonBehaviors/Entitlement.html

Note the second-to-last example of a sense of entitlement:

  * An irate customer demands products and services
    that they have not paid for.

Unfortunately, attempting to argue logically with a person who has a sense of entitlement never works. They just want what they want and, to them, it's normal behavior.