Same here. But I guess I got the smallest CLI. 300 to 500 after 5 months. I'm hoping it'll go up again sometime soon.
I kept getting the same denial of increase letter when I attempted a cli over the net. Third time I called, talked to a rep. She said " That product has a $750.00 credit limit.".( my limit started at $500. then jumped to $ 750.).
She said I could apply/request a different card with higher limits. I kindly denied the offer as I did not want a HP. I keep the card around, use it for internet purchases, etc. so the payment history remains.
I have two of their cards. Both started at $500, both bumped to $750 after the generation of the 6th statement,one was bumped to $1,750 at the 1 year mark and the other remains at $750.