PostBank Post Office...took my money yet again...

So I bought shares from Phuthuma Nami Share Scheme ..today I decided to find out about the pay out and I was told that they have been depositing my money into Post bank. The lady from Postbank call center ( Cynthia)gave me attitude and told me my account doesn't exist. There no money as the account was long closed. No one know where is the money and clearly no one wants to help me. Post bank says no money in my my old bank account...so it means I am fighting a losing battle with Post bank Post Office yet again.