WARREN, R.I. (AP) _ Families who moved into a new development on the Warren-Bristol line had no idea they were moving into a black hole of the U.S. Postal Service.

Three months later, when they had not received any mail, the families knew something was wrong.

Christmas cards did not arrive at Patricia Laferriere's home until this week, and creditors did not believe that the family didn't get its bills, Mrs. Laferriere told the Town Council on Tuesday night.

When she checked with the Warren post office, Mrs. Laferriere said, she was told that t in communication,'' said Warren Postmaster Frank A. Halm, who said he would write to the creditors to explain that Mrs. Laferriere really did not get her bills.

Halm said his clerks were supposed to forward the mail for 14 homes in the development to Bristol, but instead sent the mail back to Providence stamped ''no such address.''

He suggested that Mrs. Laferriere use Bristol as her mailing address. But she said she pays taxes in Warren, has always lived in Warren and wants a Warren address.

Halm and Mrs. Laferriere were more enthusiastic about a solution proposed by Council Chairman Walter S. Felag Jr., who suggested that the Warren post office deliver the mail to the 14 houses at a central bank of mailboxes in the neighborhood.

''That's fine,'' Mrs. Laferriere said. ''I just don't want to have to change my address again.''