XAMARIN FORM consuming WCF error

Dear support,

I am register an DOT net WCF service, and trying to consume it through Xamarin CPL. I got this error when start calling the service. I have upgrade the System.ServiceModel.Primitives to 4.5.2 but still not help.

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{System.IO.FileLoadException: Could not load file or assembly 'System.ServiceModel.Primitives, Version=4.5.0.2, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
File name: 'System.ServiceModel.Primitives, Version=4.5.0.2, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
at ADATimeSheet.ViewModels.TimesheetDetailViewModel.<>c.<<-ctor>b__9_2>d.MoveNext()
at System.Runtime.CompilerServices.AsyncVoidMethodBuilder.Start[TStateMachine](TStateMachine& stateMachine)
at ADATimeSheet.ViewModels.TimesheetDetailViewModel.<>c.<.ctor>b__9_2(TimesheetDetailPage obj, Timesheet tsheet)

}