So I had this same thing happen to me. I was being charged $14.03 every month to my bank account from what appeared to be amazon. Keep in mind, I have never used my bank account / debit card for charges on Amazon. The unauthorized charge kinda of appears like an Amazon Prime membership monthly charge $12.99 + tax (depending on state / local taxes), which could add up to $14.03.
I called Amazon and talked to a representative. I gave them what appeared to be a transaction #, but she couldn't locate that # (It appears it wasn't a valid #). She then had me add my Debit card associated with my bank account to Amazon, to be able to better locate the $14.03 transactions, and see if some other Amazon account was using my debit card. Well she couldn't find anyone in the amazon system using my Debit card. She told me to contact my Bank and dispute the transactions, and I could go ahead and delete the Debit card from my Amazon account.
So long story short, its a fraudulent charge, contact your Bank or Credit Card company as soon as possible and dispute the charge. I called the fraud department at my bank and they confirmed it was a charge to my Debit Card, and did appear to be from Amazon. They cancelled my Debit Card and issued me a new Card.