Worst bank ever

Long story short, I have a credit card with a R15000 limit and i signed to say that the maximum amount to be taken off was 15% of the amount i owe and i was told the amount would never exceed R1750, I just got an sms that R12000 was taken from my account leaving me with -R7000 in my account and its because the agent who was going over my settings with me over the phone had changed my payment amount from 15% to 100% despite me signing the 15% contract. I now sit with -R7000 in my account and all my debits are bouncing so thanks for that also the amount has not reflected into the credit card so i cant even take the money back so thats down too and the card division were so unfriendly telling me there is nothing that can be done about it, even writing this i am so mad i am now in a negative amount with bouncing debits and no credit card even. You people are truly the worst bank and i left FNB because i thought they were bad but nothing like this ever happened over there. oh and yes i logged a complaint with nedbank and nobody has phoned me back ***. you have put so much stress on me and done so much damage to me financially and this is not the first problem ive had with you!