Checks are only sent when you have raised at least $10 for the month. If you are certain you have raised over $10 for the month and have not received a check, please be sure to check your email spam folder to ensure the check isn't there. The check is sent from the email address firstname.lastname@example.org and is sent on or near the 20th of each month.
You should also check the payment email under your campaigns settings to ensure the check has been delivered to the correct email address.
If you still cannot locate your check please email support and they will immediately look into the issue.