Online Dispute Resolution
Under special legislation of the European Union since February 15th 2016., solving all disputes regarding online shopping throughout the EU will be possible through the ODR platform available here.
It means if you run into a problem when shopping online in the EU (faulty products, inability to replace products, etc.), your complaint can be simply submitted on the above link.
The platform is available for merchants and consumers. Complaints can be submitted in any of the 23 official EU languages.