What is the purpose of this message?

Hello, Mr. Jones. This is Marty White calling to let you know that we have canceled your order for building supplies. Unfortunately, you have not paid for the last three shipments. Therefore, we see no alternative other than suspending our products and services to you. Also, if you do not pay what you owe us, we will be forced to take you to court to recover the money. We regret having to take such strong action,but we see no better way to deal with the situation.
Number 74.What is the purpose of this message?
Number 75.What is the job of Mrs. White probably？
Number 76.What will happen if the matter is not resolved?