I had a very bad experience with Vivid White Smile and associated companies. After ordering a sample and cancelling any additional product, as per their instructions, they continuing billing and will not stop.
The only option to stop them from stealing your money when they have your credit card number is dispute the charges with your credit card company and cancel that credit card because they will charge and charge that card they have.
When I originally contacted to cancel future products they said they would send a form but that never came.
I keep calling and calling and finally they said I was cancelled but they lied. They can't be trusted.