National RV Detroit Gabrielle and Steve Internet

 Purchased a new 2016 Jayco Class C in Tampa FL. Need warranty work done ( minor) Return to Detroit area every May for 5 mos. Called National Rv in January ( from FL) to schedule a service appt. Spoke with Nikki, Scheduled appt for June 11. Called in April to re-confirm appt. Steve answered , told him why I was calling. First thing he asked me was..... Did I purchase the RV from them? I told him no, but that I already had an appt. He transferred me to Gabrielle, First thing she asked, was...... you guessed it. She told me that they were totally booked and basically could not help me. So is it legal for dealerships to deny service, if you didn't purchase the unit from them??? And they sell that make of unit??? I am asked from other dealerships, the same question!