A customer sent a message to my business' Facebook page and asked how he could place an order. I told him that we were out of stock but he said his wife was unwell and could really do with my product as soon as possible, so I explained that I could send it to him sooner from the US, however at the time I didn't explain that he would have to pay customs tax. He was sent the product and contacted me explaining that it wasn't working out and that he wanted a refund. My business is still relatively new and I have been experiencing some issues with people returning goods because my returns address was a PO BOX (and I know very well now that couriers don't deliver to PO BOXes). Long story short, the customer is now irate claiming that he has had to pay to return the product (which is approx. £6 and it's in my returns policy that the customer is responsible for returns) AND for the customs tax for the shipment of the product from the US to the UK. He's refusing to pay the customs tax and said that unless my business covers it, he will seek a chargeback from his card company. I'm happy to refund the customer, however, given it cost me $100 to ship the product in the first place, I'm not keen to cover the customs fee. If I issue a full refund to the customer for the price of the product will he still be able to claim a chargeback for the customs fee? Surely they are separate things?