The Rangers Supporters Trust made the claim as Duff & Phelps released its latest update to those owed money following the Ibrox club's collapse.
The firm reported it had booked more than 8300 hours of work at an average hourly rate of £383 during the process so far.
It also revealed it has accrued a total bill of £3.18m for six months' work on the business, formerly The Rangers Football Club plc.
It addition, Duff & Phelps charged £104,608 for proposing the company voluntary arrangement (CVA) to creditors of the Old Firm club plus £42,760 prior to the administration.
The CVA did not succeed so the assets of the business were subsequently sold to Charles Green's Sevco consortium and Rangers began this footballing season in the Third Division.
Mark Dingwall, board member of the Rangers Supporters Trust, said: "Duff & Phelps has not been good value for creditors and certainly has not done well by Rangers.
"I think they [the administrators] have been very badly conflicted from the start. I think the job was far too big for them, they had no experience in football and I doubt they will be given work like this in the future simply because of the catastrophic manner they have carried out their tasks."
Duff & Phelps had been accused of a conflict of interest because one of its partners, David Grier, advised Craig Whyte on his takeover of Rangers.
The firm said in the creditors report that it has provided documentation to the Court of Session and regulatory body the Insolvency Practitioners Association detailing "conflict review procedures" taken prior to the administration.
The report lists law firm Taylor Wessing – which is assisting in a case against Collyer Bristow, the law firm that represented Craig Whyte in his takeover deal at Rangers – as receiving more than £1.2m by August 13 this year although it is due a further £340,000.
Biggart Baillie, another law firm, was paid almost £500,000 for assistance in placing Rangers into administration and advising on other legal matters.
Public relations firm Media House received £112,500 and English media consultancy Spreckley was paid £28,941. Property agency Lambert Smith Hampton received £25,000 for valuing Ibrox stadium and the Auchenhowie training ground while more than £50,000 was spent printing and sending correspondence to creditors.
The administrators took in £111,607 from the administration of Pritchard Stockbrokers which was investigated by the Financial Services Authority earlier this year over concerns about use of clients' money. The sum paid relates to the sale of Arsenal FC shares held by Rangers.
A claim of £223,214 was lodged by Duff & Phelps but it is unlikely the full amount will be recovered.
Duff & Phelps is also pursuing Uefa over payments for Rangers players representing their national teams and £800,000 in deferred transfer fees.
The firm said it anticipates being able to distribute funds to preferential and unsecured creditors but could not say how much each can expect to receive.
A spokesman for Duff & Phelps said: "As we have stated throughout the administration process, which is nearing its end, administrators' remuneration is a matter that is subject to regulatory guidelines and a matter for creditors to approve.
"Fees and estimated fees represent standard Duff & Phelps charges. These have been fully transparent and this is now the third creditors' report in which they have been detailed."
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