FNB Credit card issues

In order to downgrade a credit card from premium to gold with FNB an operator told me that I couldn't do that telephonically. I had to mail ********** I did so literally 6 or 7 times only to get the same generic response of "we are tending to your problem". I went into the branch, they too couldn't help me. It seems as though they just ignore requests in order to bully me into taking the premium card as this rewards them with higher bank costs. Where to from here?