Some merchants will issue a test charge, before submitting the final charge, as a way to ensure the payment method is valid and there are funds to cover future expenses. The test charge might still show up after you have cancelled your subscription. These usually go away in a day or two.
However, if you are unsure about any charges, we recommend reaching our directly to the merchant you used to create your subscription (Amazon, Roku, iTunes, Google). They will be able to confirm if a final charge was issued or not. They'll also be able to process a return request. If you run into any issues doing this, or have additional questions please let us know.