Forced to have an account with FNB that I cannot close

I went into the Bryanston Shopping Centre Brnach today to close a savings account that is not in use. I was told it cannot be closed. Why is a person forced to keep an account from FNB in your name. I should be able to have it closed. I also had to get back to work and was told that the branch manager would have to authorise the closure of the account but was in a meeting. I had to get back to work and was told that the branch would then close the account in the interin and that the branch would call me during the day. No one has called and the account is still open. I find it very unnacceptable that I feel like I have no right to control what bank account I have active as FNB just simply does not want to close this account.