Budget - Budget claims car was returned a week later then it was

My dad picked up from budget on June 28 at Bellevue, WA. Car was scheduled to be dropped off at Canada Place in Vancouver on June 29 and that is when it was in fact dropped off. At the time the clerk told my dad that since it was rented from Seattle they would need to process the return so he couldn't give him a receipt. The rental price was supposed to be $79.

My dad left the car there, boarded cruise to Alaska and flew home to IAH on July 11. When He got home he noticed his card had been charged $720. He called Budget and they are claiming the car was returned on July 6 at Seattle airport.

It sounds to me like something funny is definitely going on here. I have no idea how they can screw it up this badly and how can a car possibly get rerented with the computer not picking up the error. If it wasn't rerented how did it get to Seattle airport. Any ideas what to do?

Most likely the American and Canadian computer systems used by Budget are different which is why your father's American contract couldn't be closed by a Canadian computer. The vehicle was likely re-rented back to Seattle on a Canadian contract and when it was run back through the American computer system in Seattle it pulled your father's contract as the only open American contract for the vehicle. It's a fairly common mistake that can be easily solved by your father providing copies of his cruise and air itineraries.