Call the number on the back of your card and challenge the charges.
I suspect those charges are not from Roku at all. A bad guy who knows what he's doing can list his charge as anything he decides to call it. The CC company will be able to track the charge back to see who actually received the funds.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T