Letter of Reference

I have asked the Premier Banking service of FNB for a letter of reference regarding my bank account and that the account has been conducted in a satisfactory manner. First Premier Banking told me that they must ask FNB for the letter. After a week of no reply I went to a branch in Pretoria and they told me they are not authorized to give such a letter and that Premier Banking must issue this letter. While being at the branch they phoned the person on the email at Premier Banking and convinced her that it is their duty to issue such a letter. Premier Banking agreed and said the letter will be emailed to me within 45 hours... I am now waiting for more than week! It is just a simple letter, not like I am asking for money or any difficulty and i need this letter for my business. What must i do next in order to get this letter, threaten FNB, screaming wont help, commit ***** and write and write the letter myself??? Pathetic FNB shame on you!!!