After receiving just one electricity bill in 18 months, Towradgi pensioner Donna Colvin received five this week totalling $624, dating as far back as September 2012.
This was despite Mrs Colvin having arranged to pay $70 a fortnight since July last year and being told by electricity provider EnergyAustralia that her account was in credit to the tune of more than $1600.
Mrs Colvin said the last bill she had received was in June 2013 - and that was the first for that year.
"Yesterday I open up the mailbox and I've got five bills and I've never been billed in all this time," Mrs Colvin said.
"They've taken my $1662.18 credit and now state that I owe them $624, on top of the money they've taken."
She also received a bill for $325 for the last quarter, which she is not disputing. Her concern is that EnergyAustralia did not send her a bill for almost a year before sending five that are based on estimates of usage rather than actual meter readings.
"I told them I expected to get billed every quarter after getting that six-month bill [in June 2013]," she said.
"I was never billed at all, so I kept on paying the $70 a fortnight, and now they're demanding I pay them $624.
"Why wasn't I billed? If I didn't have enough, why wasn't I contacted? Their excuse is 'it's the accounts department's fault and you still owe us'," Mrs Colvin said.
"They could have sent me a bill in the mail; they never bothered. Not even a phone call. Nothing.
"Now they're demanding I pay this 600 and something dollars. It's just wrong what they're doing to me - I'm on a pension."
Mrs Colvin said she had yet to pay the $624 bill.
"I'd like to not pay it," she said. "I don't see why I should be held responsible for their mistakes."
An EnergyAustralia spokeswoman admitted there had been an extended delay in Mrs Colvin receiving her electricity bills.
"Unfortunately, a system error has led to a delay in issuing Mrs Colvin's electricity bills," the spokeswoman said.
"If a customer receives a delayed bill, we are able to arrange longer payment periods."
The spokeswoman apologised for any inconvenience this had caused and added that EnergyAustralia was reviewing Mrs Colvin's account and would contact her to discuss the matter further.