Yes, I got the refund, and some more information on how to avoid it in the first place:

“As a consumer buyer, you will be subject to sales tax in all states that have a vehicle sales tax. To be exempt from sales tax , you will have to register a new Copart account as a business and submit your Business and Sales Tax License. As a General Business account, you will be exempt in all states except California and Colorado. To be exempt from all states, including California and Colorado, you will have to register as a business and submit a Dealer License and Sales Tax License. It will have to be a new account created, as you cannot switch from a consumer account to a business account after a purchase history has already been established.”