Acts 16:16 reports, as per Young's Literal Translation:
And it came to pass in our going on to prayer, a certain maid, having a spirit of Python, did meet us, who brought much employment to her masters by soothsaying....So apparently this girl had the same spirit of divination that inspired the Oracle at Delphi.
Paul shortly exorcised the spirit out of her in the name of Yeshua the Messiah.
It seems to me that Acts 16 testifies that there have been real demon-inspired prophecies at various times and places in history. It's not all just "mumbo-jumbo".