I agree with @renojim -- If you didn't have a Roku account, and you never gave Roku your credit card number, how could Roku charge anything against your charge account?
When a "bad guy" somehow gets your credit card number and places a bogus charge, he can fill in the charge description with any text he wants. If a charge says it's from Roku, that doesn't necessarily mean it IS from Roku. The more likely sounding he can make the charge seem, the lower the likelihood that it will be challenged.
I would treat these like any other bogus charges and challenge them with the financial institution through which the charges are arriving. Don't tarry as there may be time limits on when you can dispute a charge.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X