Fnb is a disappointment

Once again fnb disappointments me I opened an business account with I mentioned I will be dealing with clients I had one unsatisfied client who asked for refund I refunded then the client went on to contact fnb reporting account fnb didn’t bother to communicate with me what they did is to close my acc which has my personal funds rather then holding the funds reported I’m not happy with how fnb handled the matter can they release my funds then hold the funds reported while they investigate the matter I have proof of people back the client I doubt the person even handed and proof or evidence to fnb I’m so disappointed with this bank!!!!