Double VAT payment on exchanging imported goods

Hi everyone, I am a UK resident and bought an LV bag in France. When crossing customs I paid import VAT (20%) for that purchase legally. But when I exchanged the bag in an LV retail in New Bond Street London, they refused to recognise the import VAT paid (even though I showed the receipt and proved my legal VAT payment on customs), which should top up to the value of this purchase. They only acknowledged the value excluding 20% VAT during this goods exchange. This led to a double charge of 20% VAT, approx. 400 pounds on me, contrary to the principles of fair taxation and I feel I was mistreated and also charged unfairly as a customer. Can the HMRC do anything about this case of unfair double VAT charge? I wanna show this case to you and hope can get some help or feedback. zechuan

Hi zechuan gong,
Please fill in form C82 if you have paid too much tax or duty and need to apply for a refund.
Please send it to the address on the form:
Request a refund of overpaid VAT or duty for goods declared using the Online Service for Passengers
Thank you.