Worst experience BP Thornton

Had a very worst service at BP Thornton service station. Petrol attendant erroneously rang R100 twice from my account instead of once. They could see from their side the error but they do not want to give me refund. My argument is why don't you give me my refund and sort your in-house problems. The manager in charge who is smelling liquor threatened me saying I am insulting him saying I must not talk about in-house (not sure what it means to him). I called the police for intervention as I fear for my safety and I am waiting......