Delta unable to provide zero balance receipt?

The title basically says it all. I’m currently in PCS status going from Hawaii to the East Coast. I purchased my own flight to my leave location and am driving up to my new PDS. I called delta to obtain a zero balance receipt but the best the agent said she could do was just showing that the card was charged. Obviously I also have my bank statement to show that it was as well but has anyone run into this issue before? Is there a memo or something I can do to fix it? Thanks-