The Hong Kong-based airline said on its Twitter and Facebook pages Wednesday that it would still welcome passengers that bought the business-class tickets from Vietnam to Canada and the U.S. at economy prices earlier this week. The online ticketing foul-up meant return fares of as low as $675 from Da Nang in Vietnam to New York at the front end of the plane, or a small fraction of its original price.

“We do not want to go back on our promise to our customers,” Cathay said on its Twitter account. “We made a mistake but we look forward to welcoming you on board with your ticket issued.”

While the passengers were kept happy, the mistake adds to the embarrassments for the carrier that’s struggling to turn its fortunes around while competition intensifies from Chinese and budget airlines. The pricing gaffe comes on the heels of a sophisticated hack on Cathay’s computer systems last year that exposed private information of 9.4 million passengers in the world’s biggest airline data breach.

Gary Leff, a travel and loyalty-program blogger on View from the Wing, wrote on Dec. 31 that the Cathay business-class round-trip from Da Nang to New York started at $675 for travel in August. On Wednesday, the same journey cost around $16,000 for July and September, according to the airline’s website. Prices weren’t available for August.

Travel from Hanoi to Vancouver and back in a mix of business and first class could cost less than $1,000, according to a post on One Mile at a Time.

Other airlines have made similar pricing errors. Singapore Airlines Ltd. in 2014 and Hong Kong Airlines Ltd. last year honored business-class tickets mistakenly sold at economy fares. The carriers didn’t disclose how many people purchased the cheaper tickets.

Cathay had sold tickets to the U.S. and other destinations from Vietnam in a promotional offer that ended Dec. 31, according to its website. Round trip business tickets to Los Angeles were sold from $2,940.