Unfortunately, the recall function does not work with PoliteMail as the way sending is performed is completely different than how that function operates. To "recall" a message you will need to stop mail flow and clear the emails out of the queue. This can be performed by a PoliteMail user with Admin privileges.
Please see this article on how to perform this action: Stopping an Email Message in Progress
Please note some message may deliver due to the speed at which the messages are replicated and sent, however if you use this feature you will be able to minimize the damage from the message.