You didn't say how long you have had your Rokus or when you set them up, if you did them yourself, etc.
With your numerous problems, I would probably go to https://www.roku.com, deactivate the device and start up a new account with a different email address with new passwords and PINS before channels can be added or purchases made. There is no charge/fees for setup of the Roku nor is there any paid subscription to use the Roku.
I would also dispute the 3 Days Free recurring charge with your credit card provider and notify them of suspected fraud.
When you setup the Roku again, you have to carefully follow the screen prompts and provided links correctly. There are some fraudulent sites out there/browser redirects/incorrectly typed browser addresses that some have run into when trying to activate their devices. If this was not your issue, your email account or network security may have been compromised at some time providing payment info if you did not sign up for these services.