Called on the 30th of November to move from Business insurance to Personal

Called on the 30th of November to move from Business insurance to Personal. Everything was fine. But I was shocked that they debited the weekly premiums for business insurance instead of the pro rata for personal. I ended up calling them again and they did activate personal insurance again, the pro rata was debited. But they still tried to debit weekly premiums for business. It's only now I'm getting a cancellation letter.