They take a years fees of my account

Mutlichoice have just taken a years subscription's money of my account without my permission. When I phoned in, they checked on the system to find out I am a monthly subscriber. They said they will reverse it, but it will take 2 weeks. Luckily my bank let my debit orders go through, but now I am in o a overdraft because of this. R8500 is allot of money if you did not budget for it and how on earth can their mistake take 2 weeks to fix