When Gippsland resident John Moll, 54, queried his Slater & Gordon bills, they came back almost double the original amounts. Across the two bills – for a workers compensation case and superannuation claim – Slater & Gordon billed Mr Moll $6126 for contact with him over nearly three years ($37 for each letter, $22 to leave a message or take a phone call, $18 for every email opened).

When challenged on the bills – one of which Mr Moll took to the Supreme Court – Slater & Gordon reverted to the original bills, a total of $27,433.  The company says this was a discount and that its billing practice is industry standard and not unusual.

"Our goal is to provide affordable legal services to everyday people – over charging or unjustified costs goes against not only the foundations of our business but the very core of our mission and our values," a Slater & Gordon spokesperson said.

But former Slater & Gordon lawyers have spoken about unrelenting budget pressure in the past five years in the listed law firm. And several were concerned that the famous firm was overcharging clients. "In my view the costs being sought (from the client) were excessive, they just didn't stack up," said one senior personal injuries lawyer, who declined to be named.

Legal experts earlier this year urged regulators to audit Slater & Gordon over fears that clients' interests might be put at risk as the firm scrambles to repay its debts to banks. The firm announced a nearly $1 billion loss in February after it purchased a troubled British legal and compensation claims business called Quindell last year.

After hurting his back pushing a faulty roll-cage at Coles Traralgon in 2012, Mr Moll engaged Slater & Gordon on his compensation case. It did some conciliation work and lodged an impairment claim, but the case stalled as the injury remained unstable. When he changed lawyers, Slater & Gordon billed Mr Moll $14,183. He asked for an itemised bill, thinking this amount was high. The new bill totalled $23,916. When his new lawyer challenged this 12-page bill, Slater & Gordon reverted to the original amount.

A similar thing happened to his claim for income protection and Total and Permanent Disability under his superannuation insurance. (The Association of Superannuation Funds of Australia recommends claimants do these themselves, but it's a growth industry for firms like Slater & Gordon. Last year the association accused lawyers of "milking" up to 35 per cent of disability payments and charging "$3500 just to fill out a form").

Slater & Gordon was successful in getting Mr Moll about $12,000 of income protection, but his TPD claim was rejected. For this he was charged $13,250. Again, this seemed high to Mr Moll. So he requested an itemised bill, which was suddenly double the original: $26,496. He took this bill to the Costs Court of the Victorian Supreme Court and Slater & Gordon backed down, again, to the original amount.

The fine print of Mr Moll's cost agreement shows Slater & Gordon charged the upper end of legal rates – those applicable to lawyers acting in Supreme Court cases (Mr Moll's conciliation with Coles briefly appeared in the lesser Magistrates Court and his superannuation claim never reached court at all). On top of this, Slater & Gordon charged an extra 20 per cent due to its "specialist expertise and experience conducting personal injury litigation". Then it added a 25 per cent "uplift" fee, like a success fee, for taking on the risks and costs of no-win, no-fee cases.

A Slater & Gordon spokesperson said charging at Supreme Court scale – and 120 per cent of Supreme Court scale – was a common form of charging in Victoria and was considered mid-range until recently.  "In recent times, Slater & Gordon has changed to just the Supreme Court scale due to changes in the scale itself and the introduction of uniform laws across Victoria and New South Wales.  This has now become the industry norm."

The Slater & Gordon spokesperson said that in some cases it charges at Supreme Court rates or above for superannuation claims "where the claims are complex". The firm only takes on superannuation claims, the spokesperson said, when it can add value and sometimes it advises superannuation claims clients they do not need Slater & Gordon services.

An experienced Melbourne personal injuries lawyer, familiar with the way Slater and Gordon charges for these matters, believes the firm "pumps up" its superannuation insurance files by increasing the contact with the client. Mr Moll was billed $286 for 13 messages the firm left him over the time he was a client.

Mr Moll was also billed for lawyers to read the relevant insurance policies ($1983) and medical reports ($1196), even though the reports had been read five months earlier in Slater & Gordon's personal injury department. When Mr Moll, who was desperately running out of money, rang to discuss accessing financial hardship through his superannuation fund, Slater & Gordon billed him $29 for a six-minute conversation with a clerk.

The itemised bills show that – while photocopies were billed at 26 cents a page - a clerk must be paid to attend the photocopy enclosure, and each visit costs $22. On April 30, 2014, Slater & Gordon drew up eight letters to doctors on Mr Moll's behalf, with each letter requiring a separate "attendance" by the clerk to the photocopy enclosure ($176).  "I'd just had enough, it was beyond a joke," Mr Moll told Fairfax Media. "The impression left by Slater & Gordon was not one of social justice, but of financial gain at the lowest risk."

In another case lodged this year in the Costs Court of the Victorian Supreme Court, Gippsland resident Samantha Kobiela challenged Slater & Gordon over a $44,000 bill in a medical expenses matter. Ms Kobiela became a quadriplegic in a swimming accident and was later involved in a road accident. The matter has recently been settled following a media inquiry about the bill.

The Victorian Legal Services Commissioner could not confirm or deny whether it has launched an audit into Slater & Gordon. The legal regulators in NSW and Queensland also did not respond to Fairfax Media's requests for interview.