"It was so busy. There were heaps of people everywhere," she said.
The shoes weren't discovered missing until later in the evening when their son was leaving for work.
"I felt sick," she said. "We were just inundated with people buying things."
They don't blame the buyer as it was just a mistake, but desperately need the orthotics back.
Mrs Aston said her son, who is flat-footed, had worn orthotics since he was a child and without them experienced severe back pain.
"We aren't worried about the shoes and we could replace the orthotics but that could cost about $500," she said.