I have a WebServiceHost that is being used to host some web services in a console app. I added a service reference to it in my client app and create the proxy like so:
It seems you have created Proxy code using Add Service Reference dialog in VS. VS ASR dialog doesn't support WCF REST fully, so, the proxy code is missing [WebInvoke] attribute. Can you try adding [WebInvoke(BodyStyle = WebMessageBodyStyle.Wrapped)] attribute on operations in client proxy?