As PKramer stated, as long as you post at least 30 meaningful posts in a given calendar month you have the basics to request your Posting Bonus for that month.
If you've already submitted your request for September in September, you just have to wait until October 31st. If you haven't submitted a request for your September posts, you still have time to make a request. Just make sure that you click on the drop down menu in the Posting Request Box to select September and that each of the 3 posts you selected were made in September.
Any Request for the posting bonus made in October will be paid (if approved) on/about Nov 30th.
Note for the future: this type of question you can present in the Support section of the Forum. It's only queries that have nothing to do with FC that belong in the Off-Topics section.