Social care providers in Yorkshire are having to make cuts due to financial pressures
Charity HfT, which supports adults with learning disabilities, carried out the survey across almost 80 social care providers, many of which help vulnerable people in Yorkshire.
It found that a third said they had had to cut staff in the past 12 months, while nearly half had closed down parts of their organisation.
One in five meanwhile said fewer people were being offered care as a result of tighter purse strings, so that the care providers could pay rising wages and balance the books.
As a result of this, staff morale has dropped while complaints are on the rise, the charity reported.
Billy Davis, public affairs and policy manager for HfT, said the social care sector had "run out of options", with the sad reality being that a lack of cash was impacting on people, not just processes.
Mr Davis said: "A lack of alternatives has left providers with no choice but to make decisions culturally at odds with the way they want to run their organisations, such as handing back services and, ironically, shedding staff in the midst of a sector-wide recruitment crisis.
"It's clear that at its heart social care funding is, and continues to remain, a national issue that requires a national solution."
HfT's research was carried out by economic consultancy Cebr.
The charity is now calling on the Department for Health and Social Care to bring forward "long overdue" proposals on reforms for the long-term future funding of adult social care.
Josie Dent, from Cebr, said: "Pressure on social care providers to cut costs while also paying for increasing wage bills and agency worker fees has ultimately culminated in organisations taking drastic measures.
"The share of providers now offering care to fewer individuals doubled compared to last year's survey.
"Meanwhile, the proportion having to make internal efficiency savings, close parts of the organisation or hand back services to local authorities remained high.
"The sector desperately needs more funding in order to provide the same level of care and support to the people who need it."
A Department of Health and Social Care spokesman said: "Everyone should have access to the best quality, compassionate care and we are providing councils with access to an additional £1.5 billion in 2020-21 to meet rising demand and continue to stabilise the social care system.
"There are complex questions to address, which is why we will seek to build cross-party consensus. But, as the Prime Minister has said, we will deliver on our promises and bring forward a plan for social care this year."
Unison assistant general secretary Christina McAnea said: "The Government's complete failure to fund the care sector is devastating the lives of vulnerable people and their families.
"Staff have warned for years that care is in crisis and in desperate need of immediate investment.
"They simply can't deliver proper care in 15-minute homecare visits while being paid poverty wages."