Britney Spears's legal team has accused the singer's father of trying to "extort" her as they called on him to immediately step down from his daughter's conservatorship.
Jamie Spears, 69, has agreed to relinquish control of the pop superstar's finances, though has given no timeline for doing so.
He has overseen his daughter's multimillion-dollar estate since she was deemed incapable of looking after herself in 2008, though she has fought to have him removed from the role.
In a new legal filing, Spears's lawyer Mathew S Rosengart has demanded Jamie Spears step down as soon as possible and accused him of trying to extort money from Spears.
It is alleged Jamie Spears is asking for about $2 million in payments to his legal team and former business manager Tri Star.
In the latest round of a bitter legal fight, Mr Rosengart said: "Mr Spears and his counsel are now on notice: the status quo is no longer tolerable, and Britney Spears will not be extorted.
"Mr Spears's blatant attempt to barter suspension and removal in exchange for approximately 2 million in payments, on top of the millions already reaped from Ms Spears's estate by Mr Spears and his associates, is a non-starter."
Vivian Thoreen, Jamie Spears's lawyer, has been contacted for comment.
Jamie Spears's legal team filed court documents in August saying he would step down and help with an "orderly" transition in the case but argued there are "no actual grounds" for his suspension or removal.
That came after Spears, 39, twice delivered bombshell testimony to the Los Angeles court, describing the conservatorship - a legal arrangement usually reserved for the very old or ill - as "abusive".
Mr Rosengart said Jamie Spears's immediate removal is necessary and has asked Brenda Penny, the judge in the case, to remove him at the next hearing on 29 September
.
He also told Jamie Spears that going voluntarily immediately would be the "legally correct, decent and graceful thing to do".
He said: "The world heard Ms Spears's courageous and compelling testimony. Britney Spears's life matters. Her well-being matters. Every day matters. There is no basis to wait."
Elsewhere in the filing, Mr Rosengart accused Jamie Spears of wanting to be praised for his role in the conservatorship before he exits.
Jamie Spears's lawyers have long argued it was his astute management of the estate that saved Britney Spears from financial ruin.
Critics - including fans in the #FreeBritney movement - claim he has been exerting too much control over Spears's career.
Mr Rosengart said: "His his idea of 'orderly' is to hang on until someone first brands him 'father of the year' and awards him a gold star for his 'service'.
"In other words, although Mr Spears has, at last, been forced to recognise that it is best for his daughter if he departs now, he claims the right to drag his feet because it is best for him to cling to this conservatorship until he feels sufficiently-vindicated."
The filing adds: "Mr Spears must resign or be suspended no later than September 29, 2021."
Mr Rosengart was installed as Britney Spears's representative in July, replacing Samuel D Ingham, who had been in the post since the singer was placed under the conservatorship after suffering a series of mental breakdowns.
The high-powered Hollywood lawyer immediately signalled his intention to take a more aggressive approach to eventually ending the conservatorship - a move made more likely by the removal of Jamie Spears.
Jodi Montgomery remains the conservator of Britney Spears's personal affairs, a role she has held since 2019.
Source: Press Association
