The Internal Revenue Service is gearing up to be hated even more than usual due to a “miserable” tax filing season, the agency’s commissioner warned. That’s because of a lack of funding from Congress combined with increased responsibilities.

The 2015 tax filing season “will be one of the most complicated filing seasons we’ve ever had,” IRS Commissioner John Koskinen warned at the American Institute of Certified Public Accountants (AICPA) National Tax Conference in Washington, DC Thursday. “All we can do is try to maximize our services as well as we can; as well as we can is still going to be miserable. You really do get what you pay for.”

Koskinen followed National Taxpayer Advocate Nina Olson ‒ who’s been in that role since 2001 ‒ at the conference. And she was even gloomier with her predictions.

“The filing season is going to be the worst filing season since I’ve been the national taxpayer advocate; I’d love to be proved wrong, but I think it will rival the 1985 filing season when returns disappeared,” she told the audience of tax practitioners, according to Forbes.

Nearly half the frustrated tax filers who call won’t be able to reach the IRS in 2015.

“Phone service could plummet to 53 percent,” Koskinen said. That number is a massive decrease from “an already unacceptable 72 [percent]” during the last filing season, Forbes reported.

Olson also noted that taxpayers who do manage eventually to get a person at the IRS on the other end of the line in the upcoming filing season will have waited on hold for an average of 34 minutes. For the practitioner priority hotline, that average wait time is expected to be 52 1/3 minutes, making “priority” a dubious adjective, she said.

It will be even worse for those filing outside the US. “If they are overseas, who are they going to call? There is not toll free number,” Olson noted.

The IRS commissioner blamed budget woes for the upcoming poor customer service. The House has voted to cut the IRS budget for 2015 by $341 million, and the Senate has proposed to increase it by $240 million ‒ which would still be seven percent below the agency’s 2010 funding levels, Forbes reported.

But the tax agency also has increased responsibilities with its decreased funding: The IRS is in charge of implementing the Affordable Care Act (ACA, better known as “Obamacare”) and the Foreign Account Tax Compliance Act (FATCA).

Olson said she’s very concerned about the IRS receiving accurate information from the health exchanges. It won’t be the IRS’s fault, but taxpayers will likely put the blame on the IRS.

Another program the IRS will implement for the first time this filing season is one of voluntary oversight for return preparers. Koskinen wants it to be a mandatory program, but that hasn’t occurred yet. In the meantime, there will be a page on the IRS website with a database of qualified tax preparers, including unregulated preparers who chose to participate in the voluntary education programs. Attorneys, CPAs and enrolled agents, who all have separate licensing requirements, will also be listed.

There is also the issue of tax extenders ‒ a collection of over 50 bills that need to be passed by the lame-duck Congress before the end of the year, with no guarantee they will become laws, according to Forbes. Koskinen warned that if the uncertainty continues into December, it could delay the start of the filing season and delay tax refunds.

“The continuing uncertainty about the extender legislation imposes stress not only on the IRS but the entire tax community, including everyone in this room,” he said.

He also wants Congress to pass penalty relief for taxpayers affected by the IRS’s shutdown of its e-services over the Columbus Day weekend, the Journal of Accountancy reported.

But it may be difficult for Koskinen to receive any cooperation from Congress, where the agency is deeply unpopular after a seriesofscandals.

“IRS Commissioner John Koskinen is going to spend so much time testifying to congressional committees, he may as well bring a cot up to Capitol Hill. His agency’s budget is likely to be slashed even more deeply,” the Tax Policy Center wrote. “But under GOP pressure, will Treasury and IRS back down on regulatory efforts to curb corporate inversions or control the use of 501(c)4 non-profits by political organizations?”

Koskinen’s AICPA conference speech wasn’t all doom-and-gloom, however. He noted that the IRS is doing a much better job of combating tax identity theft, calling it “one of the three or four most important issues we’re dealing with.”

After criminal investigations, arrests, and sentencing of between 1,200 and 1,500 individuals, plus better refund safeguards, improper payments to identity thieves are now lower but still a significant problem, with an anticipated 3,000 to 4,000 victims likely this coming year, the Journal of Accountancy noted. The IRS issued $3.6 billion in potentially fraudulent tax returns for tax year 2011, down from $5.2 billion in 2010, according to the Treasury Inspector General for Tax Administration.

“We’ve gotten most of the amateurs off the street; what we’re left with is organized crime here and organized crime syndicates around the world,” Koskinen told attendees. The IRS is also doing a better job than before of correcting victims’ accounts, reducing the time required from a year to under 120 days, “which is still too long,” he noted.