Sasfin Cancellation of contract

We've sent through a cancellation notice on 30/9/2019 as our contract would end 31/10/2019. After numerous follow ups without any response and we still get your monthly invoice. If you phone Sasfin, (if they answer) you get put through from one person to the next and nobody can assist you. I feel it is really unacceptable for a company to treat their customers this way.