1. call the insurance company to cancel the insurance. If you purchase from telemarketer, you can have 30 days cool down period.
2. If they refuse to cancel the insurance, call your credit card company to DISPUTE the charge, which means the credit card company will credit back your charge. The worst situation is that you lose one month payment.
3. For unauthorized use of your credit card, your maximum responsibility is $50. But you have to inform your credit card company if you find you lose the card or some unusural charge.
4. Lots of credit card companies provide fraud free internet shopping. You are not responsible for any unauthorized charge.
5. PUT EVERYTHING IN WRITING. for example, write to the insurance company to cancel, not just call them.
I hope it can help you.