Billing Error

I was charged for premium service but I am not subscribed to Premium according to Account Status. And I do not want Premium service. How do I request a refund?

http://ooma1.custhelp.com/app/chat/chat_launch

Need assistance? Call our Customer Service team at 1-888-711-6662 Monday - Friday 7am-7pm PST, Saturday-Sunday 8am-5pm PST.