Managed to dodge the Hello Darlings ****, now FNB holding my refund?

FNB have put a third of my funds in my account on hold without any communication. After many many calls to the ***** department I find that there is an investigation that was opened on the account due to the refund I received from the Hello Darlings travel company that is currently in the news for taking people's money.

I explained to the investigating officer that I was a customer of Hello Darlings and I painstakingly fought them until I received my refund last week, I emailed him proof of invoice as well as proof of payments yet the money still remains on hold. I've done nothing wrong, why should I receive no communication and then not be able to pay my suppliers out of my business account due to funds on hold? Surely I've furnished enough evidence to see that I received MY money back, and my own bank should not hold me ransom for absolutely no reason?