FNB is taking us for granted

FNB is taking us for granted. My money is locked for 24 hours before it's released into my account. I deposited funds (100k) to my client from my business account to the client's business account on Saturday the 20th of April 2024. This was from FNB to FNB, so the expectation was for the funds to clear immediately. FNB then flagged the transaction for ***** and verification which I am already used to and somehow understand how it helps protect against crime. The SLA for this process is 12 hours and the expectation was for this process to have been completed the same day or at least first thing the following day. They apparently called me on Sunday the 21st of April 2024 around 13:00 to verify if I am the one who did a transfer. They said they could not get hold of me and therefore reversed the transfer. Now, the funds are not reflecting on both the client's account and on my business account as well. I asked FNB where the money is, and they said it takes 24 hours to clear. This is taking its toll on my small business. I cannot understand why the money which was transferred from FNB to FNB will be held somewhere and not be returned immediately.