FNB SAVINGS ACCOUNT CLOSED

I need help. My salary gets paid into my saving account. I downgraded my account and FNB said that my account number would not change, however my savings account linked to that account did not reflect. I went to FNB and they said that my savings was closed, I did not know that and I need my savings account back as it is urgent that I get my salary as I have many responsibilities. Please assist urgently.