01The fourteen days
Because you bought at a distance — a website, no shop to walk into — EU consumer law gives you 14 days to withdraw from the contract without giving any reason. It is a right, not a concession, and nothing on this site can reduce it.
The clock starts on the day you, or somebody you named, physically take possession of the goods — not the day you ordered, and not the day of dispatch. Where an order arrives split across several parcels, it starts on the day the last of them reaches you.
You must send your decision within those 14 days. Sending the goods themselves can come afterwards; it is the notice that has to be inside the window.