Credit Limit Decline

I have had my Amex Credit Card for more then 6 months and pay promptly on time and always more more than the requested amount due, I thought I would enquire about a credit limit increase, apparently this cannot be done on line, you have to phone in and request the limit increase, 2 phone calls later and about an hour on the phone, my request was declined, reason: affordability. My salary was increased 1/6/15 and my expenses have come down, I have requested a review on the decline of my credit limit increase by resending all my payslips (4 months) and bank statements (from Jan 15 to current), what alot of red tape!<br> <br> I hope this matter can be cleared up.