An Air New Zealand customer is furious the airline withdrew $400 from his account after overpaying him compensation for a sub-par flight.
John Roncoroni says he never gave the airline consent to remove the money, paid after he was placed on a plane "full of rubbish".
But Air NZ says he was notified of the overcharge after a "system error", and still received the original "goodwill" payment of $400.
Mr Roncoroni and his wife bought Air NZ tickets from Auckland to Perth in 2017, but were instead placed on a Portugese carrier, Hi Fly.
"The plane was full of rubbish and my head rest fell off," Mr Roncoroni told Newshub.
"The plane was not properly ventilated... whilst on holiday and soon after our arrival in Auckland, we both became ill, which we believe was the result of the condition of the Hi Fly plane."
Air NZ told Newshub it is" proactively contacting customers" if they are to be placed on Hi Fly flights, while its own Boeing 787-9 Dreamliner fleet undergoes unexpected maintenance.
But determined not to face the same discomfort on their return flight in January, the pair opted to take an Air NZ-operated detour to Christchurch, saying it added "significant additional time and inconvenience" to the journey home.
After complaining, Mr Roncoroni received $800 in his account from Air NZ, which he "felt adequately reflected our loss of enjoyment from both journeys".
However one week later, two $200 payments were made from his debit card back to the carrier, which he claims he "had not consented to or provided authorisation for".
"I called my bank and they said that this transaction can't be made without my consent or authorisation. I spoke to their fraud team who offered me the chance to cancel my card to stop any further transactions.
"I didn't think this was necessary as I'd be without a card, have to change my direct debits and [was] sure this was a simple error on behalf of Air NZ that can be fixed easily."
"My wife and I have both raised the legality of the purchases with Air New Zealand by email, telephone and Facebook and have only been ignored or told that they are within their rights to make purchases from our account to rectify an error."
Air NZ says customers were offered alternatives to the Hi Fly service, including alternate travel dates or a refund.
"This particular customer was notified on 19 December via both email and SMS."
As a "one-off goodwill gesture" it agreed to give the couple $400 back after their unsatisfactory flight.
"Unfortunately while processing payment to this customer a system error occurred which duplicated the payment meaning $800 was paid.
"We notified the customer and apologised and advised we would be reversing the duplicate payment."
Mr Roncoroni believes Air NZ should have "taken it as a loss and moved on".
Newshub has contacted the Ministry of Business, Innovation and Employment for comment.