Delta Airline rules put new grandmother in a bad situation

Date: June 2012
Airline: Delta
Location: North Carolina

The reason I am writing is because Delta cancelled a return flight that I had. I booked a round trip ticket from Colorado Springs to North Carolina for June 5th and to return to Colorado Springs on June 30th. I had to get an earlier flight out to North Carolina for an emergency delivery for my daughter's baby.

I am already in North Carolina but I needed that return flight that I paid for and already had booked so I can return home but Delta cancelled my flight and is now trying to charge me a $100 flight change fee plus an extra $700 for a new flight. It is crazy and immoral. My flight should not have been cancelled and I should not have to put out extra money. What can I do to get home because I do not have the money to get another flight? Thank you for your help!

-Karrie