Originally Posted by
guv1976
I think you need to re-contact the DOT and ask them how you go about getting a refund of an improperly-charged U.S. tax if the carrier is uncooperative. You might also request that DOT contact BA directly about this.
I did, they said it's the IRS's jurisdiction. And the IRS doesn't have an email contact form, so I'll have to give them a call when I have some time.