Buyer claims order never arrived

As the title says, the order shows it was delivered early today and only just now they messaged me saying they can’t find it. What should I do? They haven’t raised an issue yet and obviously I’m not going to refund them, because then I’ll miss out on the money and the item, but I’m not really sure what to do..? Idk why they’re telling me without contacting vinted. Does anyone know what’ll happen if they do contact vinted? Will I end up without the money and the item? This has never happened to me before so I’m a little stressed out.