【正确答案】[范文]
March 17
Dear Mr. Smith,
   This is Wang Gang, marketing manager from Carry Trade Company. I'm writing to ask about the payment of our products.
   You have already received NO. ST218 washing machines under the contract for two months, but didn't offer us the payment. We have sent you a collection letter several days ago but received no response. We hope that you can comply with the contract to pay us the money. The deadline is March 30, and if at that moment, our company still doesn't receive the due money, we will submit the case to court.