Lufthansa double charging

If anyone is thinking of flying Lufthansa, think twice. They have charged twice for one flight we booked and still after trying to get our money back for a week we have had no such luck. how do they take money off a card, when the payment has gone through nine days before when the actual flight is booked. They are not giving us our money back and keep on making empty promises that that the money will be put into the account. Not acceptable lufthansa!!!