Thrifty Car Rental No national support! Cars are not maintained West Palm Beach Nationwide

I rented an SUV from Thrifty in West Palm Beach. Drove it from West Palm to Charleston SC and it  had a bad vibration. It needs a front end alignment or tire balance. I called Thrifty and was told to take it in to the nearest Thrifty to exchange the vehicle, so I called the Thrifty office in the Charleston airport.  They told me I could not exchange it in Charleston because it's not a "corporate" Thrifty. It's a private franchise Thrifty and they do not honor corporate exchanges. So I called Thrifty 800 number and was told the closest corporate office for an exchange was in Charlotte!  I asked about getting a repair and was told if I want to get it repaired while I am in Charleston, they will charge me because I didn't buy their insurance!!  I paid to rent a well maintained vehicle.  I should not have to pay for repairs that are not the result of an accident  Where is the service?   Never again! Pay the extra $20-50 and go with Hertz or Avis. The peace of mind and service are worth it!