A heavy glass atomiser is a large part of what a bottle of scent costs.
Once you have one, a refill is the liquid and nothing else. Bring the bottle in on an appointment day, or send it with the delivery when we bring your next order, and it comes back filled with the same batch code recorded.
We will only refill bottles that came from us, and that is a safety decision rather than a commercial one. We cannot know what was in somebody else's atomiser, and the residue changes what we put in it.
Refills still need a batch, so the four week wait applies unless we happen to be filtering something of yours already. We will tell you the date when you order rather than afterwards.