1234, Main Street
Boston, MA 02123
04 April, 2005
<Recipient Address Goes Here>
Re: Account No. <Account number>
This is to inform you that your account is [no. of days] days past due with us.
We request you to please send a payment of [$ ??] without any delay to avoid this account becoming delinquent. If we do not receive the payment within [no. of days] days from the date of this notice, we will have no other choice, but to practice hard means to collect the debt.
In case you are facing financial difficulties due to some unexpected circumstances, and not being able to pay now, you can contact us to discuss possible solutions for you.
Thank you for your attention in this matter.
encl: <List of enclosed items goes here>