Double Debited

Travelstart double debited me, leaving me with not a cent in my account. They say they can only reverse the money in 48 hours. I told the lady I don't have a cent in my account and I only got a sorry. I also complained on twitter and they not responding. I asked to speak to a manager, the lady put me on hold, came back and said the manager will get back to me in 30 minutes time. Its over a hour later and still no call. 48 hours is to long, i don't think its fair that i must wait on my own money, especially that they in fault here. I don't know what to do.