Blocked my account without any explanation

I am so disappointed in FNB. I honestly do not know how they can still be in business yet they go and block accounts for no reason. My bank account was blocked more than a week ago and I constantly call them but can’t get any answers. At first they told me my account is investigated by the ***** division and I should contact a Thabo but for the past 10 days I’m calling this Thabo at the ***** division but get no answer. Now I contact fnb again and I was told that a John is now on my case but even this John can’t be reached. All fnb staff I spoke with have no clue what is going on and fnb cant give me an explanation. This is beyond disappointing. How can u treat your customers like this?