debited me twice

Fnb debited my bond twice from my account when I call I got Palesa huma i asked for immediate refund she told me that i should fill the forms of refund, i told her that i can't do that because it's not my fault that they debited me twice, they just must reverse my money because i still need to pay other credits on time she refused, i asked to speak with her superiors she also refused I'm really angry at this kind of customer service,