The best-known rule in consumer law, and at the same time the rule whose starting point is most often explained wrongly.
Fourteen days, counted from the day you received the product, not from your order. Where an order is delivered in parts, the last consignment counts. If the retailer did not inform you of this right, the period is extended by twelve months.
Article 6:230o(1) of the Dutch Civil Code distinguishes situations. For a service the period starts on the day the contract is concluded. For a consumer sale it starts on the day you, or someone you designated who is not the carrier, received the goods.
If you order several items in one order that are delivered separately, the day the last one arrives counts. Where delivery consists of several consignments or parts, the last consignment counts. For a subscription with regular delivery it is in fact the first that counts.
Retailers often count the period from the order date. With a week's delivery time that costs you half your cooling-off period.
The duty to inform about the right of withdrawal is in article 6:230m(1). If the retailer fails to comply, the cooling-off period is extended. Informing you late but within that period restarts the fourteen-day period from that moment.
This is one of the few places where consumer law carries a genuinely heavy sanction, and it comes into play more often than you would think: many small retailers have no model withdrawal form and no findable explanation of the period.
Article 6:230p lists the exceptions. The most important in practice:
A retailer invoking an exception must demonstrate that it applies. Packaging you opened is not a seal, and a standard product with your name on the invoice is not bespoke.
You may inspect and assess the product as you would in a shop. If you go beyond what is needed to establish its nature, characteristics and functioning, you are liable for the diminished value. That is article 6:230s(3). But the same provision also says: if the retailer failed to inform you about the right of withdrawal, you are not liable for that diminished value.
This is the confusion that brings us the most files. The cooling-off period is a right to walk away from a purchase without a reason. Non-conformity is a failure by the seller. Anyone who receives a wrong or broken product does not need to invoke their cooling-off period and is therefore not bound by returns conditions or by the fourteen days. See who pays the return costs.
Practical consequence: if your product is broken and the fourteen days have passed, you are still in a strong position. The conformity claim runs for years.
Unambiguously and provably. An email is enough. The model withdrawal form is permitted but not mandatory. What matters is that you can later show when you withdrew, because the fourteen-day refund period runs from that moment. See the refund deadline.
Then the fourteen-day period is running and the retailer is in default by operation of law once it expires. Submit the case.