FNB handed me over to Debt collectors without contacting me first

I had an account that was no longer being used , FNB closed the account and handed me over to Attorneys for 2 months outstanding charges . I got no communication on this , FNB said they tried to contact me but the email address was incorrect which could not be true because they use that email address to send me monthly statements. I went into a FNB branch and they were not able to help be because the account is closed . They gave me Attorney's details but I have been trying to get hold of them but call always go directly to hold and cannot get through to them. Not sure how a bank will hand someone over to Debt collections without any communication with their client.