I think it was the same as now: Send the email.
If you email them, and then they still charge your credit card, I am sure the CC company would refund the amount if you contested the charge. Of course that has to be in writing, too.
I don't think any company wants to be put on the CC company's abuser list. I'd bet there are some additional charges and fees (or higher percentage extracted by the CC company) if they abuse customers.
