deducting money from a cancelled policy

Recently I was involved in a car accident and my car has been written off. I completed the forms and one of the forms that I signed stated that I was no longer liable for paying insurance. However on the 2 December money was deducted from my account, upon calling them they stated that I had to call to cancel the insurance. My money can only be refunded after 21 days, I find this extremely unfair especially since I am a student and have limited income. I feel that they should not hold customers responsible when clearly they are not doing their jobs. I have sent a complaint to their online customer service and have had no response.<br> <br> Regards,<br> <br> Liesl