Was the pied housed in a tub before being mailed to you?
Maybe the tank is a complete shock to her?

I try things out of the box sometimes, you never know what might trigger a snake to eat.
I sent a large female to a friends house that hadn't eaten for me in 6 months,
she ate for him twice the night he moved her, lol.
Try a morning feed time, try covering a major portion of the tank, try giving lots of cover in the tank(newspaper or fake plants) make sure temps are right, not just "pretty close", offer smaller prey items and then as she eats go up in size slowly.

Good luck