What could be the reason for WCF Service on webHttpBinding on ASP.Net server not getting data from client using WebChannelFactory ?

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
[DataContract]
public class MyService : IMyService
{
    [WebGet] // Using WebPost causes 405 Errors
    public MyDataType GetMyData(string input) // input is always empty. ?
    {

WebChannelFactory<IMyService> factory =
    new WebChannelFactory<IMyService>(
        new WebHttpBinding(WebHttpSecurityMode.TransportCredentialOnly),
        new Uri("http://127.0.0.1/Services/MyService.svc")
    );

 factory.Endpoint.Behaviors.Add(new WebHttpBehavior());

 IMyService service = factory.CreateChannel();

 MyDataType my = service.GetMyData("input");

 ((IClientChannel)service).Close();