Outsurance won't cancel my policy

I have been an Outsurance client for 16 years. I submitted my second claim for this period towards the end of 2024. The claim was for a vehicle that is comprehensively covered and was accident-damaged after a drunk driver ran into it. Although this is an older vehicle I did not foresee any problems as it is comprehensively covered and I am not a frequent claimer. I was wrong! Outsurance app**** a salvage ratio that caused the vehicles retail value to be more than halved, and instead of repairing they insisted on writing the vehicle off. Outsurance was not open to any discussion regarding the issue and in the end I cancelled my claim and had the vehicle repaired at my own expense. I did hower decide to cancel my Outsurance policy as I was extremely disappointed in the company. I finally found a good replacement and informed Outsurance of my decision to cancel my policy today. What a terrible ordeal! I was on the phone with 3 consultants, for 33 minutes and ended up requesting the cancellation by email. My request was acknowledged and I thought the cancellation was done. But NO! I just received an updated insurance policy, and there is no cancellation. In the mean time I have taken out new insurance, and don't know how I will be able to pay for both policies if Outsurance refuses to cancel my policy with them. I honestly don't know what to do. How do I cancel an insurance policy if the insurer refuses?