昨天又询问了一下客人，客人终于回复了：

I didn't receive the samples.

Normally manufacturers send us samples at no charge -
Sorry, but I use that as a guide as to how serious a company is.

我二话没说，马上给他回复了：

We didn't receive your payment for sample cost and express cost.

Normally customers pay us these cost at no complaint.
Sorry,but we use that a guide as to how serious a customer is.