Single currency card? Or is it dual currency and using US dollars? If it is a single-currency card starting with 62, it will be converted into RMB when you use foreign currency, and you can just pay it back in RMB. If it is a dual-currency card and it is swiped through visa, master or JCB, it will be debited in US dollars. If you have bound an agreed account to automatically purchase foreign exchange and return it to a US dollar account, you can ignore it. Otherwise, you generally need to deposit the corresponding RMB and then call customer service to purchase foreign exchange for repayment