DALLAS (August 5, 2012)--Southwest Airlines' attempt to thank its online customers with a half-price ticket sale backfired as customers were inadvertently billed multiple times.

Airline spokeswoman Ashley Dillon blamed a "technology glitch" for the duplicate billings to debit and credit cards.

She said the airline doesn't yet know how many took advantage of its "luv2like" promotion that gave customers who booked flights on Friday a 50 percent discount on certain fares.

She said officials at the airline were working to refund erroneous charges.

Frustrated customers reported waiting hours to speak to customer service reps.

Dillon apologized.

The promotion was to celebrate the airlines' three million Facebook fans milestone.