Ms Mcmillan spent hours trying to get a refund after the festival moved to Auckland, but did not expect to get her money back.
"I felt foolish, but it seemed so legit," she said.
The family, including Ms Mcmillan's two children, aged 11 and 13, "went out of their way" to support the original Tauranga-based festival.
"It was a family activity for our children. They're gutted as they were really excited about the festival," Ms Mcmillan said.
Ms Mcmillan said she felt sorry for all the other ticket holders who would also not be receiving refunds before Christmas.
"It's not just about our family, it's about other people. It's not acceptable that this happened," she said.
Ticket holders had been emailed with information on how to submit their details of their financial loss, but Ms Mcmillan was not holding her breath.
The statement from the Echo Festival on its website said: "After a long and what now seems pointless struggle it is with deep disappointment we must announce that it has been resolved to place the festivals promoting company into liquidation," the statement read. "For this, for your part as customers and suppliers, and for the ignominious end to what was such a promising project I can only express total disappointment. For me this final stage has been an ugly and saddening personal disaster which has left me financially and physically broken."