@Anonymous wrote:Is everyone out there as clueless as I am? Would a CSR know?
The first question is difficult to answer without sounding condescending, and that would not be my intention, since by answering "no" I would mean; there are people out there with direct information that can be helpful to you, not that you are clueless. 
The second question, possible answer is no.
I don't have direct experience with this, but if I recall there may be a 6-month wait for credit steps, and 3 months may be a bit early.
Others can weigh in to help with your first question, and it is possible a CSR would know, but not a certainty.
What is the credit limit on the card? Sometimes that has a bearing on the possibilities.
@Anonymous wrote:His is a regular QS, not a QS1 so if I'm not wrong, he is not in credit steps. His card has a $5k limit.
You could be right in saying he may need to wait for 6 months though. I thought we'd give it ago because I was awarded CLIs after my second statement. But we all know YMMV. However the denial said nothing about insufficient experience or anything like that. Just the reason I mentioned above, that credit bureau information is missing or unavailable.
Ok, with $5k that changes the answers.
$5k is not a small initial limit, and with Capital One, there is a high probability this is The Final Limit for this card. It is possible it will not increase.
The most efficient way to get a higher limit is to keep using this card, show Capital One good payment usage for 6 months to a year, try the on-line CLI tool to see if that responds. if it does not, and even if it does give CLI, then after a year the best thing to do is apply for a new card, such as Venture, and get a multiples higher CL. The first year will be no AF, and then he can decide whether to combine the limit with the existing QS after 6 months of the Venture being open.
I've had a Capital One Platinum since 2003, it has always been $10k, and never got a CLI with several asks over the last year. I recently PC'd it to a QS, then went ahead and applied for the Venture when I heard about the combining cards option. My Venture is $30k. His mileage will vary, but it is likely a Venture in a year will be $10k or more, and that can be added to the existing QS after 6 months.
People don't like the 3 HP that Capital One uses, but this is just the way they work: if you really want a significantly higher limit, the best way is to keep your current card active, and then apply for Venture and know they will do 3 HP, then move forward with the nice larger limit.