Correios

The WSDL for Correios Web Serivice: https://cws.correios.com.br/logisticaReversaWS/logisticaReversaService/logisticaReversaWS?wsdl

The Web Service Documentation:

https://www.correios.com.br/atendimento/developers/arquivos/implementation-guide-reverse-logistics-web-service.pdf