Our bank account is frozen ..why>>

Our business bank account was frozen by FNB due to outstanding FICA requirements on 25th February 2015 without warning. I have an email on record dating back to Sept 2014 requesting info, but this is the only correspondence that I can find. We did not receive a phone call from our bank manager to state that this should be done ASAP or our account will be frozen. I understand that FNB are well within their legal jurisdiction to do this, but it was the manner in which it was handled that leaves a bad taste. We have emailed the required documents early March (this was also a mission as we are a public benefit organization and the documents are not as easy to acquire as a company). After numerous emails, telephonic conversations and many frustrating days, FNB has not as yet released our bank account. We were initially told that it would take 48 hrs ... well it has been a lot more than that and how are we supposed to operate without our bank account I ask you with tears in my eyes? My faith in FNB has now been severally tested.