I agree. Contest the charge as a billing error with your credit card company.
Be sure to follow all the rules (notice in WRITING, to SPECIAL BILLING ERROR ADDRESS, within 60 days of date of mailing of bill to you--note that a phone call, email, etc will not protect you). This usually works. If not, you have a good lawsuit under the Fair Credit Reporting Act. I know those who have made a goodly sum on these.
In any event, this is a scam. Very popular in China and elsewhere. Not permitted unless you agree to it in writing, usually snuck onto the charge slip, often with no way to refuse on charge slip. Credit card company rules do not permit this (no option) but, it is often done anyway.