That was one of the oddest things. She states that her packages (not mail) require internet to be recieved and the internet was down. Due to this system being down that requires internet to get your packages someone was able to get her packages, but they somehow magically knew which was her underwear to take before she ever got the packages. This just sounds more like Anna got her packages and lost them in the house as she has done many times before.
My guess is that the apartment complex uses old-school keyed mailboxes for mail, but a secure locker system for packages (much like Amazon pickup lockers, if you've ever used one of those). To get your packages, you go down to the mail room and scan a barcode on your phone, which opens the locker containing your package. Before I moved out of the city, there were apartment buildings going up all over my old neighborhood, and they all had systems like that for legit security reasons (namely, deep blue city, turning into a crime-ridden shithole).
If the power's out, or there's no internet, however, the packages can't be put into the lockers or retrieved from them, so in that case the packages may either be left out in the open, or held for delivery until power/internet is restored and the locker system is working again. In Anna's complex, which is only half-occupied, and by people who are decently prosperous and can reasonably be expected not to steal their neighbors' mail, is probably not surrounded by homeless camps, and is unlikely to be a target for pro mail thieves, they were probably left out in the mail room.
I have a hard time believing that the package was stolen, because we know Anna lies about shit, or makes up stupid stories from whole cloth, all the damned time. She was way too jovial about it—having a package stolen, especially by a neighbor in your own complex, is enraging,. Also, if it was obviously lingerie, and was stolen for that reason, most women are going to find that extremely unsettling. Instead, Anna's just laughing like an idiot and joking about it, all in that fake way she has.
And why bother to tell her audience about it at all? Nobody was wondering if she'd do a sexy lingerie haul, and waiting with bated breath for it. She could have done the haul with what she had, never mentioned the missing lingerie, and nobody would have noticed anything amiss.
IMO, there was no package. Or maybe there was a package, but nothing in it fit, despite being the largest size offered, and she had a meltdown over it. Maybe she received a box of lingerie to do a sponsored haul and forgot about it, or it was a disaster, and her only way to deny responsibility was to claim the package got stolen from the mailroom because the power was out. Who the fuck knows. But since this is Anna, and Anna makes shit up all the time to make herself sound more interesting or hide her own fuckups, it's a given that #thathappened.
Also, regarding her travel "essentials" kit—she could do away with just about the entire thing if she wasn't a fatass who had to stuff her face with novelty trashfood every 50 feet or so. Actually needing that big bottle of Tums—and an anti-diarrheal to counteract its effects? That's so fat, I can't even.