I don't remember this happening in my long modelling career. Last week I ordered a couple of kits from Great Models in Utah: an Airfix Harrier GR9 and a Trumpeter J-20. I received the package and began rooting through the merchandise. The J-20 was fine, and is currently in the construction phase, and will eventually join the F-22 and T-50. For the Harrier, the outer shrinkwrap and those little Airfix sticker-seals were in place. The instructions and decals were fine. But when I took a look at the plastic, that fuselage sure looked odd for a Harrier. Turns out it was the plastic for the Bf-110!
Since I had already bought and built the -110, the kit wasn't something I was interested in. Unfortunately, when I wrote to Great Models' support email address, they have not answered in the last week. Hopefully I'll hear something quickly so I can send the 110 back and get the kit I actually bought. More as this develops.