I did not apply for overdraft

I opended a cheque account and credit card in September 2014,i was'nt told it has overdraft ,i was on unpaid maternity since September until January 2015 there was no money going to the account and i did'nt notice there was overdraft.April i saw money vanishing when i call call center they said they dont know ,OVERDRAFT has interest and as a client i was supposed to be told there is overdraft when opening the account because now it has affected my payment profile i used to love FNB as i am from Absa i regret switchng to FNB,I signed for credit card and cheque card not overdraft .To my knowledge ONE HAS TO APPLY FOR OVERDRAFT AND YOU WILL BE WARNED IF YOU ARE ABOUT TO REACH IT NO ONE EVER CONTACTED ME REGARDING THAT.I do not check balance because i know if i dont have money it wl get declined .I will move my account somewhere else there are honest and trustworthy.