Frozen account and declining a business account

I am having a great problem with FNB .firstly I wanted to open an account for business sales and was told that I only qualified for a savings account so I settled for that . after a few purchases where done FNB froze my account claiming to suspect ********** activity.i got in contact with them immediately and spoke to an investigation officer by the name of John Volmink.i provided him with all proof of purchase and invoices yet my account is still frozen and I can not fulfill my clients orders.i find this to be sabotage on me as a business owner because I will lose nearly R15k worth of business and my reliability will be greatly effected.i plan to keep taking this further until I get access to my account again this is not on.