Delta is a pain concerning 3rd. party billings. Had same problem with them. I bought tickets for reliable 3rd. parties(relatives, trusted friends, etc.) because they know I can find them good bargains (trying not to be boastful). Delta is the only one where I had a problem. I have to call & get their credit card #. (they do not mind--they know me well & trust me). It is a hassle with Delta. They told me they can not set up third party billing--they claim it is fraud issue.