This doesn't match the API which we currently agreed upon:

data: {
    addresses: [{type: "pstn", value: "+33698234520"},
                {type: "email", value: "james@operator.com"}],
    capabilities: ["call"],
    settingURL: "https://operator.com/settings"
  }

Although we don't support capabilities and settingURL atm, I think we should still support the addresses item with just the first item in the array for now.