How do I stop a hacker from using my Apple ID to steal money from my bank account?

Change your password to a really strong one. If you haven't already set up two-factor authorisation (which you can't have done if someone's getting into your Apple ID) you should do so: Two-factor authentication for Apple ID - Apple Support

I assume that this is a recurring subscription that you forgot to cancel.

If it indicates that it is being charged from your Apple ID, you can check it for yourself and cancel it. Follow the instructions on this page: If you see "apple.com/bill" on your billing statement – Apple Support