Last month she received a bill for $594 – about $400 more than the usual charge. The bill was based on an estimate of her electricity usage rather than an actual meter reading.

The same thing happened in February 2012 when a $504 bill landed in her mailbox, compared with previous bills averaged at $150 a quarter.

MORE: Elderly shouldn't have to shoulder this burden

The woman rents a unit through Huxley and Partners real estate. Agent Charles Hegyi said she had been in such a state when she received last month’s bill that he opted to take over and deal with the matter on her behalf.

Mr Hegyi said the woman – who did not want to be named due to her belief Origin would respond by cutting off her power – had paid both bills in full.

‘‘I saw her two weeks ago and she told me she was finding it hard to cope with this financially.’’ 

‘‘She said to me ‘do you think if I turn my fridge off and leave it off that will help me save power?’.

‘‘I said, ‘for God’s sake, don’t do that. We’ll get this sorted out one way or the other’,’’ Mr Hegyi said.

But that has proved to be harder  than  Mr Hegyi anticipated. After a month of getting ‘‘put through from one person to another’’ the matter appears no closer to resolution.

The calculation of the bill based on her estimated rather than her actual electricity use is at the heart of the issue.

"If they're saying they're estimating them on past bills then you would have thought she'd be getting bills around $150 to $155," Mr Hegyi said.

"They couldn't answer that, just like they couldn't answer most of the questions that I put to them.

"What's more frustrating is that they keep telling me it will be sorted out within a week to a fortnight yet when I ring them back nothing has happened."

After being approached by the Mercury, Origin assigned a case manager to deal with the woman's billing issues.

"We're working with the customer's representative and her local distributor to resolve her concerns," an Origin spokeswoman said.

The spokeswoman said Origin based its bills on meter data received from distributors, who also let them know if the reading was actual or estimated.

"If estimated meter readings have been provided by a distributor, Origin will reconcile the affected customer's account once an actual reading becomes available," the spokeswoman said.

"If the estimated consumption is higher than the actual consumption at a customer's premises, we will provide the customer with a credit."

The Mercury understands the woman did not receive a credit after paying the first large bill in February 2012.