Charlie Caldwell said he “just about keeled over and fell off my chair” when he opened his bank statement and found a mystery purchase equivalent to his fortnightly allowance.

The description on the bill said the purchase was made at “Qantas Mascot Aus” but Mr Caldwell claims not to have flown with the airline since he visited his son in London two years ago.

He said he had not visited any Qantas stores and mainly used his credit cards to pay for groceries and bills.

“It was a major shock,” he said.

“I don’t use the internet and my credit card is never out of my wallet, so I don’t know how someone could have used the account.

“I’ve read about things like this happening before but I never thought it would happen to me.”

Mr Caldwell said he took the statement straight to Westpac where staff reimbursed him the money and took down his details so an investigation could be started.

He was told the investigation could take up to two months.

A Westpac spokesman yesterday said he could not comment on specific complaints but that customers were not liable for unauthorised transactions if they had been victims of credit card fraud.

He said Westpac would contact relevant parties to investigate the matter and advised that other customers take preventative action to protect their account.

“To protect an account customers should inform us of any changes to their (details) so we can contact them if we think their account has been compromised,” he said.

“They (should) provide us with details and contact numbers before going overseas, immediately report unusual transactions and be aware of attempts to copy or skim credit card details from their cards.”

A Qantas spokeswoman said it was up to Westpac to determine how the mistake had been made.

“If this gentleman has genuinely had no transactional history with (Qantas) for two yeas he should contact his banking institution,” she said.

“Qantas will do everything it can, in conjunction with the bank, to rectify the problem if a mistake has actually been made.”

Mr Caldwell has urged other residents to check their statements thoroughly and to request that their banks issue their statements monthly instead of quarterly.

“If they (fraudsters) can do it to me they can do it to anyone,” he said.