London CNN Business  — 

Britain’s antitrust regulator is investigating whether Ryanair and British Airways broke the law by refusing to refund customers for flights that they could not legally take during coronavirus lockdowns.

In a statement on Wednesday, the Competition and Markets Authority said that the airlines may have breached consumers’ legal rights by refusing cash refunds on flights that went ahead during periods of lockdown. In many cases, the carriers instead offered vouchers or the option to rebook.

During coronavirus lockdowns, the UK government made it illegal to travel abroad for non-essential reasons. These restrictions were lifted on May 17, although the government is still advising against travel to certain countries.

“While we understand that airlines have had a tough time during the pandemic, people should not be left unfairly out of pocket for following the law,” the CMA’s CEO Andrea Coscelli said. “We believe these people should have been offered their money back,” he added.

The regulator said it would seek to resolve its concerns with Ryanair (RYAAY) and British Airways, which is owned by IAG (ICAGY), before enforcing consumer protection legislation through the courts. “Ultimately, only a court can decide whether a breach has occurred,” it added.

Ryanair, Europe’s largest low-cost carrier, said in a statement that it paid refunds in “justified cases.”

“Since June 2020, all our customers have also had the ability to rebook their flights without paying a change fee and millions of our UK customers have availed of this option,” it added.

A British Airways spokesperson said the airline has “acted lawfully at all times.”

“We have issued well over 3 million refunds and helped millions of our customers change their travel dates or destinations,” the spokesperson added. “It is incredible that the government is seeking to punish further an industry that is on its knees, after prohibiting airlines from meaningful flying for well over a year now.”