FNB IS FORCING ME TO KEEP AN ACCOUNT WITH THEM

I requested FNB to downgrade my account in February, they never did. I then asked them to close it they didnt. They have since been charging over R400 monthly fee. they are policy is that a salary needs to be deposited into the account monthly to keep it working I AM NOT USING THE ACCOUNT since feb. why is it still active? They are now expecting me to pay over R5000 before they close it.