Refusal to cancel policy

I called on the 31st of August to cancel my idirect car insurance, because I received a cheaper offer. But I was informed that since I had paid for September, my policy could be cancelled in the first days of September. I requested that they call me back - they didn't. On the 8th I wrote an email requesting a follow up, I was told that a consultant would follow up (C-***4) - no one did. I then followed up on the 11th and again I was informed that a consultant would provide feedback ( C-***0) - no one did. It is now the 14th.

Today I decided to call. As we speak I have been on hold for 20 mins!

What do I need to do to cancel my policy? I have made multiple efforts to reach idirect but they are the ones not processing my request. I will be reversing any future premium deductions made from my account. I will not be held liable for idirect's a) refusal to cancel a policy or b) incompetence.