Great upper wrong caliber - Radical Firearms 16 in. 5.56 SOCOM Upper Assembly

I ordered this for my father for Christmas. We opened gifts a little bit ago and we jumped in to putting this thing together so we could shoot tomorrow and sight it in. We got everything put together red dot mounted and I seen 5he stamping on the top of the barrel. 7.62x39!! Wait! What?? I ran back up stairs among the gift wrapping to find the box and sure enough. 5.56 socom. Somebody screwed the pouch! Now I will have to call to get this ironed out. What a mess. Good thing we seen it.