The European Commission has launched the new Consumer Redress in the EU site, which serves as a central point for finding help with consumer disputes:
Main Website: https://consumer-redress.ec.europa.eu/
List of consumer dispute resolution bodies in Member States (including Portugal), Norway and Iceland: https://consumer-redress.ec.europa.eu/dispute-resolution-bodies
For specific cases in Portugal, you can resort to national Alternative Dispute Resolution (ADR) entities, such as CNIACC (National Consumer Information and Arbitration Centre) or others listed on the website of the Directorate-General for Consumer Affairs - https://www.consumidor.gov.pt, for example:
CIMAAL – Centro de Arbitragem de Litígios de Consumo do Algarve
Av. 5 de Outubro, No. 55
8000-075 Faro, Portugal
Tel: +351 289 823 135
E-mail: info@consumoalgarve.pt
If you have an ongoing dispute related to online purchases (especially cross-border purchases), please contact the European Consumer Centre in Portugal or consult the Your Europe website for up-to-date guidance.