In reply to Oogachooga:
Buying the wrong size isn't really Sportiva's fault. You might have a case against the retailer if you asked them for advice and they said it was fine.
Poor finishing is Sportiva's fault, by way of the retailer, if it's not caused through reasonable use. If I remember rightly, within the first six months of purchase the onus is on the seller to show goods are of acceptable standard - after six months responsibility shifts to the buyer to show damage is unreasonable.
It's a bit tricky with shoes - rubber wears out, and it's not the seller's fault if, say, the buyer shuffles around dragging their heels. Glue coming unstuck or stitching coming undone is more clear-cut, however.
Not having the packaging in a case of faulty goods is immaterial