Momentum go out of their way to make your life difficult

I cancelled my Momentum policy as I sold my car. Momentum will not cancel until they can call me. I am unavailable when they call and I am not going to be wasting my time and money on hold so I can give them the very simple instruction I gave over e-mail already: "CANCEL MY POLICY". You wouldn't think it would be that difficult. You would think that in this day and age, things don't need to be done over the telephone. This is ridiculous. Just cancel my policy. It's not difficult.