More than a dozen graduating seniors at a District high school had to scrap plans for a vacation in Cancun last week after the travel company they were using abruptly canceled the trip and told the students it might not be able to refund their money.

Student Express Inc., a Denver-based firm that also operates as Grad Break Escape and Vacation Travel International, e-mailed the students late last month that "due to financial circumstances" the week-long, $860-per-person trip to Mexico was off.

The graduates, from Woodrow Wilson Senior High School in Northwest Washington, are apparently among hundreds of high school students in at least eight states whose trips were canceled recently because of the company's financial problems.

"I paid all my money. My boyfriend paid all his money, and I think others have too," said Shanika McBride, 18, who graduated from Wilson on June 13. "We were looking forward to going, but now I just want my money back."

Jim Moldane, Student Express president, said in a statement that the travel company "will do everything it can to make things right." He advised disappointed students to immediately contact their credit card companies and request refunds, and he said his company is working with other firms to get "free or greatly discounted" future transportation for students whose vacations were canceled.

Moldane blamed the company's financial troubles on the Sept. 11, 2001, terrorist attacks, saying air travel has declined significantly. He referred media inquiries to a public relations firm.

Dave Minshall of Minshall Media Strategies, the public relations firm, said Student Express "has no assets. The bottom fell out of the student travel market, and they are trying to refinance to get back on their feet."

It is unclear how many Wilson students were affected by the trip's cancellation or whether other students in the region paid the company for similarly canceled vacations.

Wilson student Rashaun Armstrong said she was promised a free trip if she signed up 30 students for the Cancun getaway. She said 19 or 20 students paid all or part of the required $860. Most used a credit card; some made partial payments by check.

A spokesman for Visa said such credit card transactions are generally protected by federal regulations if the cardholders do not receive the purchased goods or services. He said the disputed charges must be reported as soon as possible.

Students who paid by check could face a more difficult time. Minshall said he did not know how they can be paid back. He said the travel firm will meet with its bonding company "to see how much they can cover" for refunds.

Student Express has been in business since 1993 and arranged more than 100,000 vacations for high school and college students, Minshall said.

The Denver-Boulder Better Business Bureau has received more than 100 complaints about the company, according to reports in the Denver Post, and the Colorado attorney general's office recently launched an investigation of the company. The company received a $975,000 loan in 2002 from the federal Small Business Administration's disaster relief program.

Minshall said those funds were not enough. When other promised loans fell through last month, he said, the company stopped selling trips and canceled most of those it had in the pipeline. It has continued trying to deliver promised trips to Colorado students.

But students in Florida, Illinois, Missouri, Pennsylvania, Oklahoma, Texas, Arizona and the District are, for now, out of luck.

"I paid over $800, and I want my money," McBride said. She said she should have been suspicious when the travel company asked for an additional $60 to cover the cost of fuel. "I've been on an airplane before, and I've never had to pay for the cost of gas separately."

Staff researcher Richard S. Drezen contributed to this report.