An overwhelming response by customers to the airline's online sale celebrating reaching 3 million Facebook fans Aug. 3 caused "performance issues at various times during the day," a statement from Southwest read.
Some customers were charged more than once for the same reservation due to the computer issues and the airline said Saturday it's working to refund those customers. Duplicate reservations are also being canceled.
"Southwest Airlines is committed to providing customers with exceptional service both online and on board. It is our goal to resolve this issue as quickly as possible and minimize any inconvenience to you, our valued customers," the statement said.
Southwest said it will also refund any financial penalties customers may have incurred for the duplicate transactions.
"For those customers who used debit cards and have received overdraft fees as a result of the additional charges, we will process a reimbursement for all overdraft fees that were caused by duplicate charges from Southwest for a single purchase," the statement said.