Delta Airlines Delta Airlines screwed up my itinerary, refused to refund change fees due to their error. Internet

Im an event promoter from Durham, NC.  We booked Roy Davis, Jr., a DJ from Chicago to play in Chapel Hill, NC on September 4, 2009.  His agent, now ex-agent double booked him so we had to move it to September 5, 2009.  We had already booked his airfare (through Priceline) from Chicago to RDU and back.  I called Delta directly to make the change. It was changed from LA to RDU then RDU to Chicago.  I gave my credit card and was informed that I would have to pay a $150.00 change fee and the increase in fare.  I understood that and it was fine.  I was told they would email me the new itinerary so I could forward it to Roy Davis Jr.  Five days later and I still had no email.  I called several times and each time they told me they emailed it.  It never came.  I finally asked them to read my email back to me and they had it misspelled.  I received the itinerary and forwarded it to Roy figuring all was well. 

Roy called me in a panic the morning of the 5^th saying that he could not get on the plane because the flight had not been paid for.  The attendant was very rude to him at LAX.  I gave my credit card in the beginning so I was not sure why it had not been paid for.  I called Delta and the representative told me that they had to resubmit it twice for some reason and I was given a new ticket number to give him and that all was good with the ticket.  I gave him the new ticket number.  He calls back saying that they reversed the itinerary.  At this point I was angry and confused.  I called Delta back again and was then told that the flight had not been paid for.  I gave my credit card again and was charged.  By this time, he had missed the flight that was on his itinerary due to Deltas fault.  To my astonishment, they charged us ANOTHER $150.00 change fee so he could get on the next flight.  I had no choice but to pay it because he could not miss the engagement for legal reasons.