Amamzon On Demand — charge on my account which was not ordered

I was charged $7.99 on 5/21/18 for amazon on demand which i did not request,. I ordered two movie videos - city island and the sixth and final season of major crimes. I already received city island in the mail and am waiting major crimes. I did not oder anything "on demand."

I'd appreciate if you could remove this charge from my account.
Thank you,

Guity adjoodani
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