Personalized interest rate

I simultaneously opened an FNB credit card account and closed another credit card with another company. I already settled the 2nd account and wasn't using it for roughly a month. Because the 2nd account was still open in my name the personalised interest rate is much higher than without the 2nd credit card, on which I was quoted in the first place. In the branch I was told that I could simply phone the number on the quotation and revise the rate once the 2nd credit card was finally closed. After back and forth phone calls to the wrong number etc. and e-mails, I was informed that the FNB account must be active for 6 months before the rate can be adjusted. Why wasn't I made aware of this from the beginning?! The opening of the account also took since middle February to complete via online application. This is now the second incident with FNB that makes me seriously consider moving to another bank. I am sick and tired of the big companies walking over the little man!