Television licence collectors have been attacked for their "poor" performance amid high levels of evasion and plummeting enforcement rates.
The BBC is losing up to £291 million a year through fee-dodging, according to a committee of MPs.
Successful enforcement cases under Capita have dropped by nearly a fifth and it has failed to drive down evasion, with the worst offenders Scottish and Northern Irish viewers, the probe found.
Collectors often find homes empty as more than half of visits take place during working hours, the Public Accounts Committee said.
MPs said they were "concerned" about the conduct of Capita staff after reports that some had targeted vulnerable residents while trying to boost collection rates.
They also hit out at the extra costs imposed on viewers who pay the licence fee quarterly using direct debit payments.
It comes as a separate report found the number of senior managers in the BBC earning more than £150,000 went up despite promises of a 20% cut.
Over five years, the BBC reduced the cost of its payroll workforce by 6% in real terms and reduced its senior management pay bill by £17.1 million.
But the number of managers on top-level salaries rose from 89 in 2012 to 98 last year, according to the National Audit Office.
The corporation also missed out on a target to reduce the proportion of senior bosses to 1% of the workforce by 0.6%.
NAO head Amyas Morse said: "The BBC's approach to managing its workforce shows definite progress. The BBC has improved its oversight of staff and achieved better value for money than in the past.
"The scale of the BBC's efficiency agenda in the coming years is considerable and the BBC will need to monitor workforce changes carefully to build on the recent progress it has made."
Around three million licence enforcement visits were made during the 2015 financial year, but 18% fewer evaders were caught than in 2010, when only 2.7 million were carried out.
The licence fee evasion rate is estimated to be between 6.2% and 7.2% across the UK, rising to 9% in Northern Ireland and 10% in Scotland.
MPs said reducing the rate "requires urgent attention", with cost of evasion estimated to be between £251 million and £291 million.
Quarterly licence fee payments cost an extra £5 on top of the £147 bill, generating around £16 million of additional revenue for the BBC each year.
But the PAC said there was "no clear justification for charging licence fee-payers more".
"Given the additional £5 charge, there may be unintended incentives for the BBC and Capita to direct people to the quarterly direct debit payment option," the committee warned.
The inquiry found that Capita was struggling to employ enough enforcement officers because staff face abuse on the doorstep, with 78 physical assaults against 73 officers in 2015-16.
Earlier this year, BBC director general Tony Hall said the TV licence collectors had ''fallen short'' of the standards the corporation expected after reports vulnerable people who had not paid were being deliberately targeted.
Capita is expected to reported its findings to Lord Hall in the next few weeks, MPs said.
The committee also warned the BBC that it must be "exceptionally careful" in the way it asks pensioners for money if it pushes ahead with plans to ask over-75s, who are entitled to a free licence, to make voluntary donations.
"Altogether, the BBC and Capita have much to do to improve evasion and enforcement performance," the PAC report said.
BBC deputy director general Anne Bulford said: "The NAO report acknowledges the BBC's approach to managing our workforce is securing better value for money, meaning we are better placed to face the challenges ahead.
"We are pleased that the NAO has also recognised the steps taken to simplify the BBC; to increase the diversity of our workforce; and to reduce payroll costs by 6% in real terms including almost halving the number of senior managers."
A BBC spokesman added: "The BBC note the Public Accounts Committee's findings and welcome the National Audit Office (NAO) finding that the BBC has reduced collection costs by 25% and increased revenue for programmes and services.
"Despite most people abiding by the law and more licences being in force than ever before, there has always been a small minority who refuse to pay the licence fee, so we'll continue to use the full range of enforcement methods and encourage people to buy a licence at every stage, as well as considering any further improvements which can be made."