In case of dispute, the consumer can appeal to a Consumer Dispute Resolution Entity: 

Under the terms and for the purposes of the provisions of art.18, paragraph1 of Law 144/2015, of September 8, it is hereby informed that the competent alternative dispute resolution entity to which the consumer may resort is:

• CICAP - Consumer Information and Arbitration Center of Porto 
• Rua Damião de Góis, 31, loja 6, 4050-225
• Phone:(+351) 22 550 83 49 / (+351) 22 502 97 91
• E-mail: cicap@cicap.pt
• https://cicap.pt/ 

Know your rights when you buy online. 

More information at Consumer Portal (https://www.consumidor.gov.pt/)