Missing pack from Mega evolutions ETB

Pattricez

I bought a Mega evolutions ETB today from my local store and only have 8 packs not the 9 as advertised. What do I do?

Thanks

Eckxile

Take photos, dont open anything and maybe the store will be gracious enough to accept a return. But REALLY it's going to be near possible to prove this unless you have a video of the unboxing of the ETB. Good luck!