title: HTTP status 400 when trying to add web service reference to a project
body: <p>I am trying to add <a href="https://api.onecallnow.com/WebService/3.1/soap.svc" rel="nofollow">this WCF service reference</a> to my Visual Studio 2012 C# project. When I try to load the service through the add service dialog, I get this error</p>
  
  <blockquote>
    <p>There was an error downloading
    '<a href="https://api.onecallnow.com/WebService/3.1/soap.svc/_vti_bin/ListData.svc/" rel="nofollow">https://api.onecallnow.com/WebService/3.1/soap.svc/_vti_bin/ListData.svc/</a>$metadata'.
    The request failed with HTTP status 400: Bad Request. Metadata
    contains a reference that cannot be resolved:
    '<a href="https://api.onecallnow.com/WebService/3.1/soap.svc" rel="nofollow">https://api.onecallnow.com/WebService/3.1/soap.svc</a>'. Content Type
    application/soap+xml; charset=utf-8 was not supported by service
    <a href="https://api.onecallnow.com/WebService/3.1/soap.svc" rel="nofollow">https://api.onecallnow.com/WebService/3.1/soap.svc</a>.  The client and
    service bindings may be mismatched. The remote server returned an
    error: (415) Cannot process the message because the content type
    'application/soap+xml; charset=utf-8' was not the expected type
    'text/xml; charset=utf-8'.. If the service is defined in the current
    solution, try building the solution and adding the service reference
    again.</p>
  </blockquote>
  
  <p>I've looked at other questions with this error, but almost all of them suggest changing something about the WCF service configuration, to which I don't have access.</p>
  
  <p>Someone suggested that the last part of the message means that I am using a different version of SOAP than the service is using, but I don't see any options to change that in the Add Web Service dialog.</p>
  
  <p>Can someone help me correctly add this service reference?</p>