FNB bad management

Went to FNB to do reversals, they sent me home telling me to do it from home on the app, they took a total of R1500 for debit orders laying in my account waiting to go off and then R100 for each debit order that bounced. Went to FNB again to tell them about this they told me that they would reverse the money they took, because the reversals was done before they took the money they never did the reversal its been almost a month now, now they keep sending me messages that my account is overdrawn by R5381 when in actual fact it is much less, most of which is money they owe me, this mornings SMS stated that they are taking legal actions against me