Refund my R8000

Hello, Good day I would like to bring this issue to your attention cause I really do not understand why fnb does this all the time, on the 21st of this month of August before I went to bed I have R40,569 available balance in my account the next day which is 22nd of August I was about to make payment for a client work I was paid days before, logging to my account I only see R32,569 I was so shocked cus this money is meant for a client birthday I need to carry out this coming days. I did my calculations then I find out fnb has already debited exactly R8000 from my account with no explanation whatsoever. I called fnb immediately and they told me the money was part of a ***** money thats why is being debited and they said an investigator in charge will contact me, up till this moment nobody is yet to contact me Here’s my case number # ***. I have nothing to do with ***** and either my business has nothing to do with it also I know nothing about it as it was money that was sent to my from a client for a birthday decoration I have my evidence and all. FNB needs to do better when it comes to this kind of issue. I’m not against them investigating but the investigator will take forever to get in touch with the account owner. They should have people’s consideration, what if this money is meant for my emergency. I need them to refund my money I have nothing to do with ***** either my business too. Thanks a lot