Blocked access from my business account

I have a business account with FNB which I ended up having to block because my business partners began misusing the funds. In an effort to change the signatories of the bank account, my partners absconded which is the why for my blocking of the account. In the absence of my business partners, I tried changing the signatories but i was told this would be impossible if there wasn't at least one of the previous signatories. This is causing strain on on my business because my clients are still paying me using that account for my services but I cannot have access to the funds in the account. I need the account to be opened in order for me to retrieve the funds.