A payment plan agreement outlines an installment plan to repay an outstanding balance over a specified time frame. This document is a cellphone payment plan agreement between a debtor and creditor.Write a letter asking for some money from my parents. Make it sound like it's from a young person. A payment agreement should always be in writing and include information regarding the type of payment to be given, when it should be given, how it will be paid. The format of the letter is not crucial. The important thing is that you must have a written agreement with the seller identifying you as the purchaser. Simple to use fill in the blanks templates. Customizable business document samples. No payment will be made on a contract with an expired.