Mr Sandles’ situation is a timely warning to mobile phone users to be clear about what the conditions of their contract entail.

The Nowra pensioner said he keeps an Optus pre-paid mobile phone for emergencies.

But recently he said it had cost him $78 in phone credit and he hadn’t used the phone.

Two weeks ago, Mr Sandles said he was instructed by text message to top up his phone credit, when his credit was down to $38.

“With $10 I renewed my credit and then got a message that said I had seven days to renew my credit,” he said.

After speaking with the manager of the Optus store in Nowra it turns out he lost the $38 credit because he should have renewed with $30 not just $10.

“I’m a pensioner and to me they’ve just stolen my $38,” he said.

“Why should I have to put $30 on my phone when I haven’t used the $38 that is still on it,” he asked.

We contacted the Optus media hotline and were told someone would look into Mr Sandles’ case.

A spokesperson for Optus said there was a misunderstanding of the pre-paid service, and the customer relations team had refunded the credit out of goodwill.