If you wish to stop receiving Notifications, you can either pause or delete those that you have already created.
Simply, select the "Notifications" option under the My Account Section, click on the "PAUSE ALL" or "DELETE ALL" button. This way, you may pause/delete all your notifications (regardless of the Communication Channel you have selected).
Note I: that the deletion action has a permanent effect. If you wish to re-start getting notifications for the same asset (Vessel, Fleet, Port), you will have to create them from scratch.
Note II: that in case you pause your existing sets of Notifications will not be deleted so that you can easily activate them again at any time by clicking on the same button.
Additionally, another way to complete the above actions appears at the right side of each set of Notifications that you may have created. There you can find the "Bin" and "II" button which you can use to permanently delete or pause the corresponding Notifications and, thus, stop receiving them.