President Trump’s former fixer and personal attorney Michael Cohen is lawyering on his own behalf from an Upstate New York federal prison, filing motions that accuse prosecutors of failing to do right by him in his continued bid to shorten his sentence.

A recent set of arguments filed Friday even accuse federal prosecutors of “character assassination” after they made it clear that Cohen was of little use to them in his bid to buy himself a reduction in his sentence after the fact.

Prosecutors have said in court filings that he lied in meetings with their office and failed to answer questions that could help them.

Cohen is serving a three-year total prison sentence — covering two separate cases — on charges of tax evasion, making false statements to a bank, campaign finance violations and making false statements to Congress in relation to a Moscow real estate deal on behalf of Trump in 2016.

Still, he has been seeking the help of the U.S. attorney’s office in Manhattan to fight for an early release since his December 2018 sentencing.

Cohen admitted to failing to report $4 million in income, cheating the federal government of $1.3 million in taxes he should have paid, and conceded that he lied to a bank to get a $500,000 home equity loan in addition to orchestrating “hush money” payments to two women — adult film actress Stormy Daniels and former Playboy model Karen MacDougal — who claimed to have had sexual relations with Trump.

Cohen, a lawyer who cut deals for Trump and lobbied on his behalf, insisted that his 170 hours of testimony to Congress as well as state and federal investigators should have earned him the support of the U.S. attorney’s office when he sought to have his sentence reduced.

He asked the Southern District of New York prosecutors to submit what’s known as a “rule 35” letter, which would recommend a sentencing adjustment to the judge, but they have declined to provide one.

Cohen wrote from the Otisville medium-security prison in New York that after he was sentenced, he provided “extensive cooperation” on topics including “Trump insurance fraud claims,” “Trump’s accretion of public space at [Trump Tower] without New York City government approval” and “Hush money payments to former love interests.”

Assistant United States Attorney Audrey Strauss said in a December filing that Cohen was not deserving of the early release assistance he wanted, citing problems with his credibility. Cohen is far from the helpful witness he insists he is, Strauss argued.

“Cohen has offered no evidence that he provided substantial assistance to this Office in the investigation or prosecution of others,” Strauss wrote to U.S. District Court Judge William Pauley. “To the contrary, the Office reasonably determined that Cohen did not provide substantial assistance after his sentencing both based on the nature and scope of the information provided and because of substantial concerns about Cohen’s credibility as a witness.”

Pauley has not yet issued a ruling.