If the bill looks like: “Roku for espn”, then you should be able to login to your account at roku.com (hopefully the same account you’re using to post this?) and cancel the subscription there. I don’t know about a refund since they say their subscriptions are prepaid non-refundable.
If it doesn’t say Roku, then you probably need to cancel it at espn.
Of course, if you just created this account to post, then, try to remember your old email address, and if that doesn’t work, try this contact page:
In addition to what @Strega listed, you might find there is no subscription listed under your Roku account page. If that's the case, you are the victim of theft of your credit card information, and a thief has used that information to submit a phony bill against your credit card. The charge was not made by Roku, and Roku cannot assist you with that as it's not under their control. You need to contact your CC issuer, contest the charge, then ask them to cancel your card and issue a new one. If your CC information has been used fraudulently, you need to cancel it quickly, as the bogus charges will likely continue.
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