The residents of apartment buildings at 2611, 2627 and 2633 Adams Mill Road NW held a block party recently as part of their continuing efforts to gain refunds of what they maintain are excessive rents and a rent rollback to 1973 levels.They also are trying to block a 24 percent rent increase that the buildings' owner, H & M Enterprises, has requested, according to Kevin Kerr, a tenant who organized the block party.

The party, which included a softball game, book and bake sale and flea market, was held in Community Park West in Adams-Morgan.

Most of the funds raised will be used to pay for the services of Gail McHugh, an accountant. McHugh has worked with tenants in three other cases in which H & M Enterprises, which is owned by Howard and Maxine Bernstein, filed hardship petitions with the city Rental Accomodations Office, asking for rent increases under a provision of city rental law that allows a landlord to raise rents above the legal limit if he can prove that he has a less than 8 percent rate of return from the building in question.

In her testimony as the first hearings last February and March on the Bernsteins' hardship petition, McHugh charged that she had discovered evidence of fraud when she examined the Bernstein's records, which tenants subpoenaed.

"In going over his (Howard Bernstein's) books I found that he has his own maintenance crews," she said in an interview. "He's charging buildings between $6.25 and $15 an hour, but he's only paying the men between $3 and $5 an hour. He also purchases supplies wholesale and charges the buildings retail prices and above."

The tenants' attorney, Charles Montange, of the Neighborhood Legal Services at 3308 14the St. NW, said that the tenants asked for the rollback and refund "mainly because of the existence of housing code violations and a decrease in laundry, trash collection and utility services."

Rents for the 105 units in the three buildings range from $139 for an efficiency to $220 for a two-bedroom apartment. The tenants must pay their own utilities.

In June, the commission decided to allow a rollback to 1973 levels and a refund of overcharges to tenants. Later in the month, however, the decision was remanded to the Rental Accomodations Office for a full hearing, because Bernstein asked for a stay of the decision. "He did not roll back the rents or give refunds," Montange said.

At an early August hearing on Bernstein's request, two tenants members of the Rental Accomodations Commission, Marie Nahikian, who is also a candidate for an at-large City Council seat, and Judy Walton, walked out of the meeting, saying they wanted to prevent the existence of a quorum at the session.

"It was an outrage . . . They (the commission) weren't following procedure. They allowed Bernstein to introduce hand-written documents. Now new evidence is supposed to be introduced. The commission is an appeals body," said Nahikian.

Despite the absence of a quorum, however, the commission granted the stay. There has been no decision yet on the landlord's appeal of the decision that he must roll back rents and grant refunds.

Howard Bernstein said in an telephone interview last week that he is now satisfied with the automatic 10 percent rent increase he got last May after the new rent control law went into effecct. He said he will not "press for the 24 percent increase" if the tenants withdraw their request for refunds and a roll back.

He denied the allegations of fraud involving maintenance and service charges, saying they were "so factually incorrect it's not even funny. People can say a lot of things at a hearing. As far as I'm concerned, we've been doing everything all right."

Julie Wall, a tenant spokesman, said that Bernstein "has never talked to any of the tenants" about the offer not to press his request for a 24 percent rent increase. "The offer hasn't been delivered to us in writing. We can't trust a verbal offer. It should be sent to the (tenants') association through our lawyer."

Another tenant, Bettina Bergo, said that some of the housing code violations have not been corrected.

At one point "the three buildings had more than 900 housing code violations among them," said Bernard Jones, a housing inspector with the Department of Housing and Community Development. But he added that, "the majority have been corrected. We made a spot check last month. Some had been repaired and reoccurred," he said.

An element of mystery was introduced into the case when two officials of the rental office and commission acknowledged that they been unable to locate the tapes made of 16 hours of testimony at the February and March hearings. Larry Andrews, chief attorney with the Rental, Accomodations Office, and Paul Krumrine, attorney for the Rental Accomodations Commission, said they have not been able to locate the missing tapes.