For Sam and Dawn Morgan, the 30-mile drive from their one-bedroom Arlington apartment to their new, three-bedroom town house in Prince William County was an obsession. Three or four times a week for 20 months, they drove to the Forest Hills subdivision near Woodbridge to lot 159, where their house was being built.

Now their dream has turned sour.

During construction, Dominion Bankshares Mortgage Corp., which financed the project, foreclosed on Forest Hills' builder, Zimpel/Silverstein Inc. The Morgans said they were promised by Zimpel/Silverstein and Dominion Bankshares that they would honor their contract for the house, which is being completed by another builder, Long-Signature Homes. But now they have been told that the town house will cost them $21,000 more if they decide to go ahead with the purchase.

"We were going down to the site every week," said Dawn Morgan, 29, a registered nurse who is four months pregnant. "We'd sometimes go there in the morning, during the day and even at night. There didn't seem to be anybody doing any work. That's when we began to get concerned."

But assured that the house would be completed, the Morgans bought a new dining-room set, four chairs and a puppy. They were ready to send out change-of-address notices when they saw a notice for a public auction of foreclosed properties, which included their home, in the classified section of a Prince William newspaper.

When they called Dominion Bankshares to find out what happened, the bank told them they had foreclosed on the Forest Hills properties of Zimpel/Silverstein.

The company that is completing the construction, Long-Signature, has raised the price of the Morgans' house from $92,000 to $113,000. The Morgans, who had put $1,000 down on the house, have been paying a monthly storage fee because they have no room for their new furniture, and Remy, their dog, now weighs 85 pounds. It is unclear what will happen to the $1,000. Ten days ago, the Morgans paid an additional $300 deposit on the house, but that deposit expires today. They are continuing to seek financing for their town house at the higher price.

If the Morgans or the two other families want to buy their houses, they must make a new deposit and pay the higher prices. "We did everything we were supposed to," Dawn Morgan said. "We were told repeatedly that our contracts would be honored. Then they dump us."

John Djurick, assistant vice president of construction loans for Dominion Bankshares, and the bank's attorney, Kurt S. Gleeson, declined to comment on the case. Zimpel/Silverstein did not return calls to the company's Falls Church offices.

The building and land development firm -- run by Stephen Zimpel, its president, and Alan Silverstein, its vice president -- has encountered financial difficulties before. Last year, the company failed to raise $10.50 million after promising to buy 25 pieces of property from a group of 22 Arlington residents who live in the Courtlands neighborhood.

One of the other Forest Hills families, Cara Quesenberry, 35, and her daughter, Jennifer, 12, planned to move into their town house last August. Quesenberry paid a $1,000 deposit in March 1987; at the time, her town house cost $87,000, but it now is priced at $109,000.

"House costs have gone up and so have interest rates," said Quesenberry, a legal secretary who has lived in an Alexandria apartment for five years. "The 'time is money' adage is very much at play."

The Morgans and Quesenberry said they never received anything in writing from Dominion or Zimpel/Silverstein explaining why there were construction delays. Much of their contact with the companies was through telephone calls during the past two years, they said.

The Morgan and Quesenberry families said they wrote their deposit checks to Forest Hill Development Corp., which was formed by Zimpel/Silverstein to build the 38-unit town house project near Cardinal and Waterway drives.

When the Morgans signed a contract on May 22, 1986, to buy the town house, Zimpel/Silverstein told them it would be completed in February 1987. But when last February came, the house wasn't ready, they said, and it is still not completed.

In July, the Morgans and Quesenberry said Zimpel/Silverstein told them it was restructuring its loans with Dominion Bankshares, which had provided much of the construction money for the project.

In August, the bank met with the Morgans and 15 other families who chose not to take a refund of their deposits and instead wait for their homes to be completed. During the meeting, Dawn Morgan recalled a Dominion Bankshares official saying that it was looking for a new builder to complete the project.

The Morgans said Zimpel/Silverstein told them through last September that it was not sure when the houses would be completed. "They told us they were having 'big problems' with the plumbers," said Dawn Morgan, who began keeping a notebook with the dates and quotes from conversations with Dominion Bankshares and Zimpel/Silverstein officials.

To protect the property from vandalism and weather, the Morgans said, the bank erected a fence around the 19 unfinished homes, installed windows in those that didn't have any, and hired security guards. But in September, with no completion date in sight, 13 families decided to take their deposits and look elsewhere.

On Sept. 30, Morgan said Dominion Bankshares told her it would honor her contract no matter what happened with the project. Two weeks later, the bank foreclosed on Zimpel/Silverstein's loans and told the Morgans, the Quesenberrys and another contract purchaser that their contracts were "null and void."

Long-Signature Homes purchased the uncompleted homes for an undisclosed price and last weekend staged a grand opening.

Cara Quesenberry said she isn't sure whether she is going to pay the higher price for the town house. "Quite honestly, I feel like we've been dropped," she said. "It's like we never existed."

"We like the house," said Sam Morgan, 37, a management analyst for the government. "It's the one we wanted."