C SURANCE IS USELESS!!!!!

Had an issue with C Surance in June, complained, got contacted and issue was "sorted out" and c surance was cancelled for both my devices... I even have an email confirming c surance on both devices were cancelled. Just got my invoice from cellC and I'm still getting billed for the terrible product! Now they expect me to spend another 35minutes on the phone holding on, to sort out their incompetence. USELESS!