楼主不是要担心怎样支付这$4000, 而是你的Merchant Account ( 信用卡服务公司) 会直接deduct $40

信用卡 as payment processing cycle:

1 customer place order
2 楼主 charge the credit card
3 merchant service company approve the charge $4000, credit card went through
4 楼主出货
5 merchant service deposit $4000 into 楼主"s bank account
6 customer receive the goods
7 customer receive the credit card statement
8 customer pay the credit card bill. 到这时楼主才是真正收到了这$4000.