DISGUSTED AND ABSOLUTE ROTTEN SERVICE RECEIVED

I am a FNB Premier banking account holder, for over 40 years. I was expecting an amount to be deposited into my cheque. I noticed a deposit was made into the account, and assumed that it was from the expected source. I transferred the said amount into my money market account. Today, I went into online banking, to use my account, only to find that my account is frozen. I am unable to use my account. Hence, my disappointment, and disgust, and the frustrations that this has caused me today, I had no access to my account, to buy my medication, for fuel for my vehicle, etc., amongst other things. I then contacted FNB via the FNB APP, secure messaging, and the attendant advised, administration blocked your account, and it is now with the ***** department. Contact FNB ***** department. I contacted The ***** department, who advised me that there was a deposit made into my account, and asking me leading questions, such as Do you know where the deposit came from? I advised them, yes, I was expecting a deposit from someone, so assumed that that is the deposit. The lady in question than stated, oh so you are not sure where the deposit had come from? I said, well you are now confusing me, as I have just stated, that I was expecting a deposit from someone, and assumed it is the amount in question. FNB ***** then stated, that I am contradicting myself.. because if I was not sure of exactly the amount expected, why did i transfer the funds out of my account and into my money market account without my contacting FNB first? I have never done this before, and It is my account, and I can do as I like with my account? I was then advised that IF YOU WANT THE ACCOUNT UNBLOCKED, YOU HAVE TO NOW GO TO THE POLICE STATION AND DO AN AFFIDAVET STATING WHAT YOU HAVE JUST SAID? and forward it to FNB ***** Focus, as your account is now under investigation? Investigation for what? For money that has been deposited into my account from a reliable source? I then contacted the source, who confirmed that the deposit was made by them. Is this how FNB views their clients? Was it not correct for FNB to contact me directly, and query, prior to freezing my account? I am totally disgusted, and frustrated at the level of judgement that FNB could stoop down too WITHOUT CONTACTING ME THE CLIENT OF OVER 40 years, and ran my account in an excellent manner?