require 'faraday'

Faraday.new do |conn|
    conn.adapter :net_http

    res = conn.delete do |req|
        req.url 'https://api.enotasgw.com.br/v2/empresas/{empresaId}/nfc-e/{id}'
        req.headers['Authorization'] = 'Basic {Api Key}'
        req.headers['Accept'] = 'application/json'
    end

    puts res.body
end

<?
require('../src/eNotasGW.php');
	
	use eNotasGW\Api\Exceptions as Exceptions;
	eNotasGW::configure(array(
		'apiKey' => '<sua api key>'
	));
	
	$idEmpresa = '484FB0C5-969E-46AD-A047-8A0DB54667B4';
	$idNFe = '10';
	
	try
	{
		eNotasGW::NFeConsumidorApi->cancelar($empresaId, $idNFe);
		echo 'Sucesso! </br>';
	}
	catch(Exceptions\invalidApiKeyException $ex) {
		echo 'Erro de autenticação: </br></br>';
		echo $ex->getMessage();
	}
	catch(Exceptions\unauthorizedException $ex) {
		echo 'Acesso negado: </br></br>';
		echo $ex->getMessage();
	}
	catch(Exceptions\apiException $ex) {
		echo 'Erro de validação: </br></br>';
		echo $ex->getMessage();
	}
	catch(Exceptions\requestException $ex) {
		echo 'Erro na requisição web: </br></br>';
		
		echo 'Requested url: ' . $ex->requestedUrl;
		echo '</br>';
		echo 'Response Code: ' . $ex->getCode();
		echo '</br>';
		echo 'Message: ' . $ex->getMessage();
		echo '</br>';
		echo 'Response Body: ' . $ex->responseBody;
	}
?>

public async Task<string> CancelarNFCeAsync(Guid empresaId, string nfceId)
{
  try
  {
    using (var httpClient = new HttpClient())
    {
      httpClient.DefaultRequestHeaders.Clear();
      httpClient.DefaultRequestHeaders.Add("Authorization", "Basic {Sua-ApiKey-Aqui}");
      httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

      using (var request = new HttpRequestMessage(HttpMethod.Delete, string.Format("https://api.enotasgw.com.br/v2/empresas/{0}/nfc-e/{1}", empresaId, nfceId)))
      {
        using (var response = await httpClient.SendAsync(request))
        {
          var resultContent = await response.Content.ReadAsStringAsync();

          if (response.IsSuccessStatusCode)
          {
            return resultContent;
          }
          else
          {
            throw new Exception(((int)response.StatusCode) + " - " + response.ReasonPhrase);
          }
        }
      }
    }
  }
  catch (Exception)
  {
    throw;
  }
}