Express Scripts Filled prescription without my consent and charged me $400 Internet

I received an email from Express Scripts saying I was receiving a prescription for $400 so I called to inquire since I don't use their mail order except for Botox and that is sent directly to the doctor.  They said my doctor had faxed them a script for Relpax so they filled it and I have to pay for it. I had a credit card on file so they charged it. I disputed the charge but I am fearful that they will still bill me.  I have not opened the package.  I called my doctor and they have no record of ever faxing it to Express Scripts in fact, they did send it to CVS where I filled it a month before for $10.  Does anyone know if there is a government agency that we can contact to resolve this?  I want to see the actual fax from the doctor. I would also like to see the documentation that says the consumer has to pay for any prescription then send.