Life turned sour for residents of 11 buildings in the Bronx and northern Manhattan in early March, when their landlord sold their apartments to Acquisition America.

Now, as they find eviction warnings slipped under their doors, many of them are wondering how much longer they can hold onto their homes. On February 28, Acquisition America bought seven apartment buildings in Manhattan and four in the Bronx — with nearly 800 apartments — from the family of Isidore B. Simkowitz, for $109 million.

Empire Management, which owns at least 15 other properties in Manhattan, created Acquisition America as an investor group in January.

Since the properties changed hands, tenants and building supers say the new owners have harassed them, failed to keep up the property — including neglecting electricity bills — and have threatened people with eviction. “When they bought the buildings, they immediately shut down every expense they could shut down,” charged Jim Harwood, president of the tenants association at 509 West 110th Street. Workers have been busy reconstructing empty apartments-one worker last week said he was turning one-bedrooms into two.

Meanwhile, Harwood claims, the company has tried to rid the building of tenants — many of whom live in rent stabilized apartments. On April 24, he and his wife received a letter from management accusing them of running a high-traffic business out of their apartment and telling them to get out by May 9. While Harwood says he does occasionally work out of his home, it does not generate traffic and is not in violation of his lease. He has sent a letter to Acquisition America disputing its claims, and is waiting for their next move. Meanwhile, state Assemblymember Daniel O’Donnell has advised other tenants who have received these notices to do the same.

Empire Management President Fred Ohebshalom denies harassing anyone. Acquisition America is sensitive to the concerns of tenants and is open to criticism, he told City Limits, but up to now, “Not even one request has ever come to us.”

The company may soon be socked with one, though. Officials at Local 32BJ, the union representing building staff, are accusing Acquisition American of unfair labor practices and are preparing to file a complaint with the National Labor Relations Board. Since the company bought the buildings, union officials charge, it has cut back its staffing levels and thrown out the workers’ union contracts, leaving them without benefits and pensions-and with lower salaries.

While acknowledging the company has done nothing illegal, 32BJ Vice President Kevin Doyle said, “Acquisition America has been predatory in its conduct regarding tenants and workers.”

Some local elected officials have also taken up the cause. State Assemblymember O’Donnell, State Senator Eric Schneiderman, and City Councilmembers Philip Reed and Bill Perkins planned to hold a town hall meeting about the buildings on Sunday, May 18. Ohebshalom was invited but said he will not attend.

That is unfortunate, said an O’Donnell spokesperson, since “we are willing to take it to the attorney general’s office.”