@Chayes1616
Unless you need access to that old email account (which is your Roku Account) in order to cancel/manage subscriptions, it may just be easier to just Factory Reset your RokuTV (press and hold reset button for 15-30 sec), and create a new Roku account (use a new email address).
However, if you really need to contact Roku, then start at the Roku Contact Us page https://support.roku.com/contactus and select "Accounts, Payments, and Subscriptions".
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