American Airlines, Frontier Airlines and Delta Air Lines were all fined for violating the U.S. Department of Transportation rules for consumer protection, said the department late Friday.

Frontier was fined $400,000 for its violations of disability and over-sales rules, while American was fined $250,000 for its failure to make refunds to its passengers on a timely basis, and Delta was fined $200,000 for the filing of inaccurate baggage reports, said the department through a formal statement.

Delta did not properly report baggage claims in their entirety between 2012 and 2015 and told the Department of Transportation that if he reported all claims it would have fallen from its fourth ranking to fifth amongst carriers for the least number of baggage claims during 2012 and 2013.

In a prepared statement Delta said it had been notified in 2016 its policy for damaged bags was not in compliance with that of the published guidelines of the department and it updated that policy immediately.

Frontier did not seek volunteers prior to bumping their passengers involuntarily, did not provide its bumped passengers the written notice required describing the passengers’ rights, and it failed to give proper compensations to its passengers in a timely fashion, said the DOT.

In a prepared statement, Frontier said it remained committed to being in compliance with all rules at the DOT, the airline added that it updated its procedures that were not effective as well as taking steps including, introducing a revamped reporting system. It also must add a new management position for quality assurance by September 1.

American Airlines did not process a substantial number of its refunds on a timely basis during 2015, said the department.

The airline said on Friday it was committed to providing refunds on a timely basis to its customers.

American added that it took a number of proactive steps in addressing the delays in refunds that certain passengers had experienced during 2015 due to an issue with systems integration after its merger with US Airways that included investments to make improvements in processing times.

Bumping practices at airlines have attracted much more scrutiny after a video of a passenger being dragged from a flight on United Airlines last April came to light.

That incident as well as others has been broadcasted across social media prompting hearings on Capitol Hill with executives in the airline industry that brought up questions about cost cutting by airlines and customer service.

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