Amazon Prime — charged when I have no account

Address:	3500 twin city dr, 51501
Website:	Amazon prime

I was charged $13.90 by amazon prime for a monthly fee and i do not have an amazon prime account called them to talk to them about it was told i need to go through my bank to dispute it. Have tried to go on line to cancel it myself and a will not allow me to cancel it. It says to go to amzn.com/bill, wa to cancel and i get this instead. The web site says i canceled my membership may 2018. This has messed up my checking account. Now i have to fix the mess this has made.