Bad response from the banish and head ofiice

I Last week (08-02-2016), I went to the branch to ask for a letter stating that my account is up-to-date. I was told the bank does not provide such letters, especially if the account is handed over to the Lawyers. I asked my outstanding balance and the contact number of the Lawyers. The branch called creditors head office and they were able to provide me with the information I needed. I paid the money that I was in arrears with and then, I called the Lawyers to ask for the letter stating that my account was now up-to-date. The Lawyers told me to go to the branch and ask for the letter as they do not issue out letters. The branch couldn't assist me. Today, I went again to ask for the letter. I ask to see the manager. She refused to see me, the consultants refused to see me. The receptionist then called the head office to enquire, head office refused to issue me with the letter. I asked what to do now as I need that letter, the manager then came and said she will send an email to head office and with the head office response she will get back to me. I need to know where to go in order to get the letter stating that my account is not in arrear?