How can I reach a human about an unexpected RDS charge and request a refund?

The charge is likely related to RDS Extended Support rather than a normal database usage change. Check the billing details and account settings first, then include the specific line item and amount in your case so the billing team can investigate it.

Some people have had billing issues reviewed successfully after contacting support by phone, especially when the charge was caused by an unexpected service transition. Be clear that you’re requesting a one-time billing review, although approval depends on the circumstances.

Open a billing support case through the cloud console’s Support Center and explain exactly what changed, when the charge appeared, and why you believe it was unexpected. Since you’re on the basic support plan, the response may not be immediate, and a refund isn’t guaranteed, but billing cases are the appropriate route.