unfair billing, misused access to accounts

I have been charged 22% more than normally this month for my car insurance. There was no notification informing about the increase and I did not expect that my premium would grow from this month. Even if i received the notification, I would need the time for a research and for making a decision if i really want to pay so much or I must change the insurer. I sent my complaint to the customer services of the company asking to refund the difference and give me the time to decide if I wish to stay with them. They refused to do so and they also mentioned that they did send me a reviewed policy on 28/02/2016. I did not receive the notification but even if it was sent, I was not left a chance to agree or disagree, because there was no time left. According to their policy, i can only cancel my insurance 30 days prior to the termination of the contract. But there was no chance to do so given to me if I am not happy with the increase. Why do not I have 30 days to make a decision? Does the contract work in the insurer's favour only? Besides, they only accept debit orders and no eft payments. They simply want to have the access to customer's accounts and charge them as much as they want.