No refund for an error on their side

I have been struggling to get a refund for more than 3 weeks. They deducted money from my bank but the online order was never processed. They keep on saying it has been escalated and then a week ago they promised the money will be refunded within 24-48 hours. Its a week later and no money yet. The staff at the call center is not helpful and they put you on hold for a very long time just to tell you they will escalate it again.