As it wasn't a Zavvi exclusive, and they didn't make it, I'm not sure what response you'd be expecting.
At best you could try returning it as defective as you were expecting it to have the title on the spine (not that it was ever pictured as such) and see what happens.
I got mine from Amazon, fully expecting it to match the first 2, and that the mock-up wasn't accurate (it wasn't, but it was close). I've contacted Lionsgate but so far heard nothing. I contacted Fox regarding the Alien(s) vs. Predator spine/front title difference and was told that if I wasn't happy I should return it to the retailer for a refund.
I'm not sure I honestly expect Lionsgate to do anything about it. The print run is done. Buy it or don't buy it is probably their thinking now. I think the best we can hope for is when they release Mockingjay Part 2, they throw in a free spine inside the box.