Offering a pre-approved 171% higher credit limit but wont consider a interest rate review of less 1%

I Requested an interest rate review on my FNB Credit Card taking into account my total exposure with FNB and conducting all my FNB Facilities in an exemplary manner not to mention the increase in the repo rate and I receive this nonsensical feedback "We have app**** all variable on the deal and rate of 16.25% is at best, we are unable to reduce the rate further". If this is how you treat customers then why are you so eager for me to increase my credit limit which is currently R88,600 to my pre-approved offer of R240 300.00 -