I am in the process of returning an item I bought from US amazon (although I'm in the UK). The package is en route back to the US, but has been acknowledged by amazon.com and I have received a refund to my credit card - but not for the full amount I paid. My original payment invoice was broken down into three parts - cost of the item, shipping costs and 'est. tax collected' of $10.94. The amount refunded only covers the item and shipping, not the tax element. How can I go about reclaiming the tax, and if this not levied by amazon, who should I approach?