How to prevent excessive requests to Transfer Family from stfp-client?

Hi, I am using Transfer Family, and I want to prevent too many download requests by sftp-users.

I set up cloud-watch alarm and lambda to stop the server in case of too many download requests.

Although lambda can successfully stop the server when too many downloads , the established sftp-connection continues and the user can download files.

Are there any way to stop too many download requests to Transfer Family?