What Ask Shelf is
Ask Shelf is an automated assistant, not a person. It says so before its first answer: "You're chatting with Ask Shelf, an automated assistant." It is open to signed-in customers, from the Ask Shelf button at the bottom of every page.
It answers questions about three things: your own orders, delivery, and coupons. It answers from these help pages and from your account's orders, and only about orders of the account you are signed in with.
When it hands you over
Some questions need a person: a refund, a return, a complaint, or anything these pages do not settle. Ask Shelf then hands the conversation over, and you can do the same at any time with "Talk to a person". Shelf is a training shop, so in this sandbox nobody replies after a hand-over.
Check what it says
An automated assistant can be wrong. The shop itself is the source of truth: the order page for an order's status and date, the cart for shipping and coupons. If the assistant and the shop disagree, the shop is right, and the difference is worth a bug report.
Each answer shows its run number and time, so you can quote the exact answer. "New chat" clears the conversation and starts the run numbers again.