Woodallr, first of all, I hope you realize you contacted a scammer pretending to be Roku (there's no such thing as a Roku subscription). It sounds like you may have given them access to your Roku account which allowed them to put your TV(s) into Guest Mode, but if you can still log in at https://my.roku.com, you can take the TV out of Guest Mode there. You need to know the email address that was used on the TV's Roku account which may be different than the email address you used to log into this "community". If you can log in, change the password.
You can also try recovery mode or factory reset if your TV doesn't support recovery mode. If you make it to the "Let's get started" page, whatever you do don't call any number you find on the Internet which almost certainly will lead you to a scammer. You may need to create a new Roku account and link the TV to that if you couldn't get into the old one.
How to use Recovery Mode on your Roku TV™ | Official Roku Support
How do I factory reset my Roku® streaming device? | Official Roku Support
