Just cannot get a limit increase for 3 years

I called the call centre this morning to apply for a limit increase and it was declined with a minute. I told the agent that I can send settlement letters to prove that I have paid up my accounts that the credit bureau. And she tells me no its declined and that's it. Not even saying sir you can forward your documents and she can manually assess the application. I am just a number or a customer? I have been trying for 3 years to get a limit increase and it is just not possible at all.