Open your phone's dialer application.
Dial Skiza Tune's USSD number *811#. This has no charges.
Manage your Active Skiza tunes by pressing "5".
Select "My Skiza" to see the ones you are subscribed to.
Select the Tune you are subscribed to and select unsubscribe to stop the Skiza Tune.
You will receive a message confirming that you have been unsubscribed from Skiza tune.
Done.