There is no charge for swiping UnionPay VISA card with Singapore glass, and the exchange rate will be directly converted from SGD to RMB. But before you swipe your card, you should be prompted to swipe UnionPay, otherwise the other party will use VISA to help you swipe it, and there is a charge. Tax refund is handled at the airport. When you arrive at the airport, you can take the tax refund form to the tax refund counter on the far right. Generally, you don't need to see your goods, just the tax refund form.