"The back door was left open," she said.
"The only things I removed were what I had paid for myself."
Mr Langdon said he intended to lay a complaint with police.
It adds to the acrimony over the failure of Ms Walker's business. She says she was not aware of the true state of the business' financial position when she bought it.
Mr Langdon said the gym had 1100 members when he sold it to Ms Walker and her partner at the time Gary Davies, who was Mr Langdon's accountant, "had full disclosure of the books".
Ms Walker said the gym had about 800 members when she made the decision to liquidate.
On March 1 and 2, 71 three-month memberships were sold on internet site Grab One for $99 each - a total of $7029.
Gym manager Jonathan Hall said all Grab One vouchers and existing memberships would be honoured and it was "business as usual" except for group fitness classes that would be running soon.
"It will be a matter of time - we have a lot to sort through," he said.