Thieving Virgin Active SA

I paid R360 per month for a long time. Then beginning of the year Virgin Active just starts deducting R720 of my account for apparently being under charged for many many months. No call was made to discuss this. When I called, they just told me this is the way and i asked for a manager to call me back. Still no call received. Companies think they can do what they want and double your debit orders whenever they please.