Low-priced phones - new or repackaged?

I was looking for a particular model cell phone today and visited a few phone stores. The prices ranged from $19,900 to $17,900.

One shop assistant who was offering this phone at the higher end of that range claimed that some of the cheaper prices were below cost. She said that the only way that the other stores could offer those prices was that the phones weren’t really new. They were supposedly phones that had been returned within the 7-day refund period and had then been repackaged (or perhaps even been faulty and repackaged after repairs).

Does anyone have any insights or experience regarding this?