We have seen this a few times now where sellers were being charged for other marketplaces and it seems to be a glitch on Amazon’s end.
We recommend getting in touch with seller central and letting them know that you are looking to cancel the professional selling plan and receive a refund for the extra marketplace, and that you are looking to stay on a professional selling plan for the US. They should be able to handle it on their end without issues.
Why aim I paying for multiple marketplaces when I only signed up to sell on one?
Why are many other marketplaces now listed in my seller central account?