Why?

Unless she's had problems before she probably never checks tracking, nor knows about Chullora and Sunshine West. I don't checik tracking,  and only know about the sorting centres from the boards

An example which is probably close to reality -

Purchase on 10/3, seller's handling time 1 day, estimated arrival 15-22/3

The 15/3 is the FIRST possible delivery date, not a guarantee. it is an eBay estimate, NOT something the seller nominates nor has control of.

Keep digging. The longer this thread is at the top, the more sellers who will read it.