@PhukRowku
Go to your online dashboard at https://www.roku.com/ or https://my.roku.com/dashboard and setup a PIN for purchases under "Device Settings".
If you don't need your payment info for any Roku Pay subscriptions, also remove your payment info under "Payment Methods".
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I have never had the above happen to me, so you actually may be getting scammed by others using Roku as an alias. You can contact Roku billing at https://support.roku.com/contactus and select Accounts, Payments, and Subscriptions for them to look into further for you.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102