Call your credit card company, deny payment.
Go to the Federal Trade Commission and file a complaint
Ignorance is Bliss, but Bliss can be expensive.
Please try and understand that your personal information is out there, even if you never had a computer and never touched the internet, there is still a huge amount of public information available, to anyone that wants it. Data is big business and business is good.
I feel sorry for folks that get scammed by companies such as this, but try to understand the internet before entering into any monetary transactions online.
They are probably not local to you, they may not even be bound by laws of your nation. They can be anywhere and do practically whatever they want.
You wouldn't hand some stranger money at your front door would you?
Hand them your credit card information?
Why in the world would you do that on the internet?
Emotional knee jerk reaction. We have something on you!
Many types of your public information is on the internet. You cannot remove it. Hence the "public" part.
There may be many types of your personal information on the internet as well.
You might can get it removed but it is quite difficult. It is an involved, time consuming process and best handled by attorneys that specialize.
DO NOT EVER put anything into or on a social website, even when you think what you are doing is private, that you would not print in your local news paper or tell your worst enemy. Same with your email.
EVERYTHING you do on the internet, mobile phone, mobile device, tablet etc etc is available to, and being saved by someone, somewhere and is worth money.
There is NO privacy. Get used to it.