Discovery Bank confiscates people's funds for wrong allegations

For some time I was banking with Discovery Bank and never had problems until recently I noticed how their customer support has just rotten. They placed a hold on my account claiming that I recieved proceeds of *****ulent money from fnb and I should contact fnb and the sender of funds but all the funds they told me about never came from fnb they came from capitec. How am I supposed to contact FNB when I don't bank with fnb or capitec? When I contact the sender and their bank they don't even know anything about this and I just feel like Discovery is putting these false allegations inorder to confiscate my funds. They never tell me straight answers when I call them, the investigators never respond and it's a dead end because I have nowhere to get help from. All this happened when I had a huge amount of money in the account but when I used to keep small funds it never happened. I just don't trust these people anymore there is something fundamentally wrong with them.