I posted an inquiry last year about Amazon's STORE (not VISA/MC) card giving me a low $700 CL... & appearing to be limited to $2500 tops via online requests for a CLI. CreditBoards led me to the Backdoor phone number, & I went from my $2500 to $10K w/ a 5 minute phone call & w/o a HP.
Here I am 8 months later, & I decided to call earlier this afternoon & ask for $15K.
After a few minutes on hold, the Underwriting fellow asked: "You have not spent more than $1300 on your card during any given month, so why do you need a higher CL than your current limit of $10K?"