Replacement for missing SL envelope?

I ordered two non foil bundles of the Marvel SL drop. One for me and one for a friend. Our package didn’t include either Black Panther envelope.

The website seems to say that in order to receive a replacement for missing cards you have to mail back everything you did receive. Is that accurate? We’re hesitant to open our stuff if wizards is going to want it in order to replace the envelopes that we didn’t get. Also that sounds incredibly pointless.