If you do not want to receive more annoying ringing of your contacts, you can turn off easily. Just log in to your MSN Messenger account and go to the Tools menu and select Options. In the left pane, you must select the Messages tab and disable the checkbox Allow my contacts to send me a buzz
From now on, when you send your contacts drones only receive a confirmation text in your window, but you will hear the sound of buzzing or tremble your window!