This as letter from Pak & Moring drafted on your behalf and sent to the debtor. It features a history of the transactions, evidence of all money owed, and demands payment of your account receivable.
This approach has many advantages: it is the quickest and least expensive action that a law firm can take to resolve your debt issues. Likewise, official statements drafted by lawyers tend to expedite the actions of debtors who are stalling for no good reason. Demand letters get attention, and are generally the very first legal step a business should take to convince a customer to pay debt they owe.