Apology to Receiver of NSF Check
When I received your letter of 12-12-2012 with my check attached marked "insufficient funds", I [list actions you made in researching the matter]. The gentleman I spoke with, [name], discovered that the bank had failed to credit my account with a substantial deposit I had made several days prior. The bank has assured me that they will be sending you a formal letter of apology for their error. Attached is my check in the amount of $50 to replace the dishonored one you have returned.