Thanks for your reply. I contacted Acorn about this, and this is their reply:
Thank you, using the information supplied we see that your Acorn TV membership was created us the Roku subscription service. Roku is a third party provider of Acorn TV with separate billing and subscription information that is outside of our direct accounts. At times a few of our third party providers, such as Roku, will add commercials with their subscriptions, they will however give you a commercial free option at an added cost. All of our direct subscription will always be commercial free at no additional cost to you.
If you would like to know how to get a direct subscription with Acorn TV that is add free please reply to this message with a contact number and a convenient time to call you. We can contact you by phone to answer any questions you may have.
The Acorn TV Team
Seems like everybody is trying to pass the buck. There doesn't seem to be any way to contact Roku directly. Help? Anybody else ever experienced commercials through Acorn /Roku?