Dear :

You have not responded at all to our many attempts to collect the $ you have owed us since [date]. Our next step is to take legal action to collect the money due us.

This is certainly unpleasant for both of us and is no doubt damaging to your credit rating. Therefore, we will delay any action for days from the date of this letter. Please let us have your check on or before [date].

Whether or not we take legal action is now your decision.

Sincerely yours,

[name]

[title]