A watchdog upheld three out of four complaints the public made about the Home Office in a year, nearly double the rate of other major departments.
A raft of mistakes by officials across government departments and agencies that left members of the public stranded abroad, caused court cases to collapse and jeopardised the safety of alleged abuse victims were laid bare in a report by the Parliamentary and Health Service Ombudsman.
Some failings were found in 75% of Home Office cases it assessed, up 6% on the previous year.
The rate was far higher than the Department for Work and Pensions, which had a rate of 39%. The Ministry of Justice had a 36% rate and just one in 10 were upheld for HM Revenue & Customs.
Bad decisions and poor communication were the top reasons for complaints, the ombudsman said.
Among the cases it investigated was a complaint about the Children and Family Court Advisory and Support Service (Cafcass), which disclosed information that would have made it easy for a former partner to trace a women who had accused him of domestic abuse.
A court case collapsed after a woman who claimed she was verbally threatened was not told about the date, leaving the Crown Prosecution Service (CPS) with no evidence to offer.
The report also revealed a woman in her eighties with impaired sight and health problems was left stranded in eastern Europe after she was wrongly refused a returning resident visa.
Ombudsman Julie Mellor said: "People complain about poor public services because they don't want the same thing happening to someone else.
"Our investigations have revealed that people's lives have been put on hold because of incorrect decisions, wrong advice and delays by public services, leaving people unable to work and separated from their loved ones.
"It is the responsibility of every board of every UK government department and agency to make sure they learn from complaints to prevent others from suffering similar injustice in the future."
A Home Office spokesman said: "We take complaints about our service very seriously and apologise to those who have been affected by incorrect decisions and advice or delays.
"However, the number of complaints we receive is relatively small compared with the millions of customers UKVI (UK Visas and Immigration) and Border Force deal with each year – and even fewer require investigation by the Ombudsman."