God will bless you for having a charitable heart, not on the end result of that charity. It's so hard to have to go through this kind of experience because it tends to make you more cynical. YOU did a good thing, she did not.
It is so hard to believe that there are people who choose to live like that, but there are. I used to live in a third world country and the poverty was staggering. There were children that would beg outside of the stores where I would shop. I used to give them money until I learned that they had been to all the shelters and missions for short periods of time, but liked their freedom more. I also found out that they had an older man that they worked for and all money they got was turned over to him at the end of the day. So I started giving them food to eat. Opened packages, 1/2 a piece of fruit or 1/2 a loaf of bread. Why you ask? Because if it was anything whole they were ordered to resell it and turn in the money. Sad, but true.