c# - Windows phone 8 consuming a WCF service operation contract error -

I have a website that I have developed, hosted by a WCF service i site hosted by a hosting company I have a Windows Phone 8 application that consumes the service. My problem every time I query an operation contract with a parameter, I received the "System.ServiceModel.COmmunicationException: Remote server returned error: NotFound" error, but if I do not ask any action that the service is working Does.

[Communication] Public Interface IParcelService {[Operation Contract] String TrackParel (String PNumber); } Public class parcel service: IParcelService {public string TrackParcel (string PNumber) {return "some string"; }}

From the one snippet service on top, I have a reference to the service on the client and I call it

  var service = new parcel client (); Service.TrackParcel ("1234"); Service.TrackParcelCompleted + = (s, args) => {Var res = args.Result; // reslt at this point throws an exception;};