Inconsistent ******* from Private Clients

I have a private clients bank account and credit card with FNB and recently app**** for a credit increase online. When I did this, the online system approved my application and I did an electronic signing of my contract for the credit increase. A couple of days later, I got an sms asking for my proof of income to be emailed, which I did by sending my last 3 bank statements. Then nothing happened for a couple of weeks and I was asked for proof of income via an accountants letter cos my bank statement doesn't show same income over the 3 month period. After I sent this, my application was declined cos of my bank statement showing different incomes, even though my income over the period averaged over R40000 as per the bank statement. I recently bought a car through the bank and this was never raised as an issue, why is it an issue now? The increase I'm looking for is a fraction of the value of the car I bought and yet that was approved. I just had my phone and laptop approved from FNB and these were never raised as issues? Why this inconstancy from the credit card division. What angers me even more is that my so-called private banker takes forever to reply, if she even responds to anything I say to her and we pay extra fees for a private banker and yet get no extra attention from them. I've raised these concern through my private banker but she has decided its not worth responding to me, well I have no choice but to make a complaint here!