Starkfan, you and I had a conversation about Gabi strap length a couple of weeks ago when I got my Gabi. I cannot imagine your frustration.
I ordered a 14" drop and that's what I got, from the 'point' of the strap to to the top of the bag, not the short straps. They do know how to measure, so I would not cut them slack (no pun intended). The SA ostrich is pretty soft and after a week of use it measures half an inch longer, which I think is acceptable stretch. It may be a tad shorter when worn because the depth of my shoulder takes up a bit more of the drop. And I am taller than you. I did the measurement off my briefcase strap so I would get the same shoulder size differential.
That outward buckle in the back of the bag is so not acceptable, especially when the piping measures different front and back. WTH? That's just a mistake by someone. My bag does not do that, and I only know the front from the back by where the knot on the handle is facing.
If it were me, I would keep it only if they offered some huge refund percentage, which may be worth it to them, but of course it must be to you. You have to ask yourself what you would have expected as a discount if you found this in a store, if you would have purchased it at all. Otherwise, you should not have to live with that kind of error.
With a tinted wine Chiara (with BOTH straps being adjusted) on order, now I am truly paranoid. And then the Emilia on order. I am beginning to think I was just lucky on my Gabi. I hope Ignes realizes that one error makes us all obsessive inspectors because publicity cuts both ways. I have dealt exclusively with Maria, but I don't know if that would have made a difference for you when the error was in the manufacture.
Do keep us informed.