Very Disappointed

I have taken out vehicle finance through wesbank my entire life. I have my bond through FNB where I have put a massive deposit on a home. I have never ever missed a debit order on either house or bond payments, I am a private client of FNB yet I am given a interest above prime. The call Centre cannot assist and keep referring me to someone else. I don't understand how much more I can do as a customer for your bank! Any other bank would love to have me as a client because quite frankly I am in good financial standing and give you a lot of money yet I get a terrible interest rate. Disappointed