When you discover a check was lost in the mail, you need to decide if you should stop payment on the check. Contact your bank and find out how much it will cost you to put a stop payment on the check. The average charge is between $15 to $30 (as of 2010).
If you mailed a check a week ago and it has not reached its intended destination yet, give it some more time. If two weeks have gone by and the check has not arrived, now is the time to call your bank and issue a stop payment. If you are not comfortable waiting this long, you can issue a stop payment at any time.
If you decide to place a stop payment on a check, you will need to contact your bank. You will need your account number, the specific check number and to whom the check was made payable.