Charged for Unwanted HDI Insurance Policy

My bank arranged for mandatory comprehensive insurance coverage through mandatory HD insurance on July 23, charging a lump sum of 17,958 TL. I immediately requested that the transaction be canceled because I intended to pay with another card. They claimed that canceling was not possible, which disappointed me. To make matters worse, they informed me that my card was allegedly disabled for online purchases, which made me wonder how they managed to charge it in the first place! I'm not sure why they won't refund the money and deduct it from my preferred card again. It's aggravating to come across such strict policies that leave customers feeling helpless. I'm requesting a refund for this charge as well as an explanation for their perplexing actions. Dealing with this ordeal has been nothing short of exasperating, and I am hopeful that a solution will be found soon.