I call them to cancel my policy with them but they still deducted on the 15th of July 2024

I call them to cancel my policy with them but they still deducted on the 15th of July 2024. I made a call asking for a refund since I have already had my new insurance with another company. They told me to send a proof of a new insurance company. I mean don't want them to cover me anymore I just want my refund with immediate effect. Thank you.