Prime charge after cancellation

Hi! I’m so frustrated and would appreciate any help. So Amazon charged me for an extra month of Prime after canceling (the charge description says PRIME and the amount and date follow the old auto renew pattern). I canceled 2 or 3 weeks ago so it was not a late cancel. I tried chat help and they passed me around telling me a variety of fishy things and putting me on endless hold. I kept trying to escalate but they wouldn’t give out names or titles of anyone on their teams. They passed me to someone on their “leadership team” for a call and he told me the charge came from an unrelated account and I needed to file a dispute with my bank and then Amazon security would investigate. This all took hours and just didn’t seem right to me. I called the bank who told me the only way to make a dispute is to permanently block my debit card. That card is tied to a lot of accounts so I went that route because it didn’t seem like I had a choice but it’s VERY inconvenient. Amazon send an automated email in the middle of the night saying they Investigated the unauthorized activity claim and found no evidence of that (so why did the guy on the phone tell me that?) so they won’t be issuing a refund. None of their communication has names or numbers so I’m tearing my hair out. Anyone have a clue how this can be fixed? I really thought they would just say the charge was a glitch and refund it. It’s $14, why are they being shady about it?