Welcome to the forum, Deuter! Great to have you here!
First, you can have a file with the credit bureaus without a SSN. In fact, you almost certainly will have a file with them before long if you have a credit card with Citibank.
So why couldn't Experian find it when you called? Here are three possiblities that occur to me (it could be any or none of these):
1) Your credit card is relatively new, and it just hasn't happened yet. If it you just got the card, give it a couple of months and check back. It may take longer since you don't have a SSN (but I don't know that for sure).
2) You actually do have a file with Experian, but the person you talked to on the phone didn't know how to find it without a SSN. I'm just guessing, but I wouldn't trust customer service to be beyond making any mistakes, especially in a situation a particular individual may not have encountered before (but I really don't know how difficult it would be to look up your file without a SSN).
3) Your reporting is ending up in someone else's file. Perhaps someone else has the same or similar name and when the report came in without a SSN, Experian erroneously matched it up with the wrong person. The problem is that if this happened, it should have associated your address (and the spelling of your name, if different from the other person) with the account (not replacing it, just adding it). And if that happened, they should have been able to find that account when you called them. But who knows -- maybe when you said there's no SSN, they realized it couldn't be that account.
I would elimiate possibilities 1 and 2 before worrying about 3, as it may take a little more work to sort out. And as I said earlier, it could be something completely different that didn't occur to me.
