A/ Call them to see why they're running late
B/ Text them (if that's a better way to communicate)
C/ Text your store manager and then ignore her for an hour when she asks if you've done A or B, only to finally reply that "you didn't have time"
If you only have time for one text, why on Earth wouldn't you text the missing co-worker? She's the one who knows why she isn't there. Me? Trust me, no one tells the boss anything so I wouldn't have a clue. But when I asked her what was going on, she replied within five minutes and we established what had gone wrong in the chain of communication within ten. So if they'd bypassed me, they would have had the situation sorted out before the store was crazy with customers, and a third person working at the store too.
Laying aside that we're all grown adults and don't need to run tattling to teacher, I'm really perplexed as to why they didn't just call her first. That seems so obvious and easy a solution - and what we always did at every previous job I've ever worked.
I guess I should ask the store owners if this was SOP with the previous manager before I get too annoyed, but I get too few days off to have them interrupted by stupid questions that could have been easily resolved without my involvement.