BB Recruiter Ghosting Flight Reimbursement for Superday

I recently attended an IBD diversity hiring Superday for a lower tier BB. I spoke with my recruiter before booking travel, and they said that flights would be covered so I provided my receipts (~$550 for west coast to NYC round trip). I attended the interview and didn't get the offer, and followed up the next week with the broader HR team to inquire about my payment. 

I don't want to burn this bridge but I'd like to get my money, is there a way to tactfully approach this situation? I'm surprised its this hard to get one of the largest banks in the world to cover recruiting expenses.