Double Taxation?

[Bafangoo]

So I was recently the successful bidder of a C&R handgun, in a firearm auction conducted by a Midwest auction house. Their invoice included sales tax which appeared to be calculated on their home state percentage. I of course paid the entire invoice.

When the gun was shipped to my designated SoCal FFL, they invoiced me for their fees, DROS, etc., and imposed CA sales tax on the full amount of the auction house invoice, including “tax on tax,” as the sender-state sales tax was included in the calculation. They told me that IF the Midwest seller had a resale license in CA, they’d refund the CA tax to my card.

Can this be correct? So if the auction house is not remitting to CA, I have to pay double taxation? Am I crazy to think that something is amiss here? Your thoughts please. Thank you.

Michael