Be Nice and Show Self-Control. Your tone will dictate if your conversation will be a success or not. Starting off in a friendly, non-confrontational manner will ultimately get a positive response from the customer. When you have the person who is responsible for paying the invoice on the phone, ask them if you can help in any way. Do they need more info? A caring approach is important. Hear what your debtor has to say and you probably won’t have to put them on the defensive. Do not take the situation personally. Your ultimate job as a debt collector is to get the debt paid in full as quickly as possible.