I must admit, the prices that you are being charged seem disproportionate.
I don’t know whether they have made a mistake but it would be worthwhile shopping around for quotes and of the quotes come out much much cheaper and the company refuses to accept that they have made a mistake in calculating how much you should pay, then you can make a complaint to the Financial Ombudsman because they are in breach of the provisions of the Consumer Rights Act 2015 for failing to charge you a reasonable price when the price wasn’t agreed.
You can of course cancel the insurance but you can only do that at the end of a 12 month period from when you first took it out because although it may seem like it’s a monthly policy, it isn’t. It’s an annual policy to which you are paying monthly and you are obliged to pay for the full 12 month period.
You also have 14 days to cancel the policy from the renewal date.
Thank you for letting me assist you with your legal question. I am glad that I was able to help.
I am not certain whether that answers the question for you or not, but I am happy to answer any specific points arising from this.
It will be my pleasure to help you again either further with this or any future questions you have