Delta Airlines Didn't use ticket - can't even donate it! Internet

In Nov, 2011 I purchased a $711 ticket for my minor child to fly to FLA.  He was not able to take the flight.  Delta said I had a $561 credtit that could be used within one year.  When I tried to use it for myself I was told that it could only be used by my son -although I purchased it, the receipt has my name on it and my son cannot legally enter into a contract.  My son is not able to travel. So, I asked if I could donate the credit to a program for military families or to offset travel costs for families with ill children.  I was told that in not in Delta's policy.  So I am out $711 and certainly will advise anyone not to fly Delta -ever.