Fnb is bad bank indeed

My dad a pensioner only receives 1500 per month on his account , Fnb consultants keep taking nearly 700 rand every month in account when we enquire they cannot provide valid reason on where that money is going clearly someone is debitting on the poor man account and no at FnB is willing to investigate this problem. It’s has been ongoing to 10 months we called the bank , we went to the bank but no one has help him on this regard . It sad to see an old man like him constantly stressing about his finances that are being ****** from his account and no one even want to help resolve the matter.