Waiting 15 days to get limit increase apll outcome

Phones call centre end April 2015 to apply for limit increase on credit card. Was told that increase was approved but admin will send doc to sign. By 5 May still not received email, phoned again and received email on 5 May 2015. Emailed all documents required, ID, payslip, bank statements and proof of residents on 5 May. 13 May 2015 phoned for outcome and was told that they will escalate to credit for speedy process. Phoned 15 May again, was told that proof of income was rejected, lady checked on scanned docs send through 4 May and said proof of income was fine and would escalate again and will receive outcome in more than 3 days. 15 days to get answer unacceptable. Was considering to transfer my account to FNB but due to this bad service will not.