Not knowing how you found out the fabric in the first place leaves some questions ...
If it was word of mouth that she wanted to get rid of some fabric it might have been relayed to you out of context.
If it was an ad that you saw perhaps she didn't have it worded clearly.
If she was an elderly lady she may have just been wanting to part with some of it and thought maybe you could make her something in exchange for it...kinda like a barter for a discounted price.
Whatever the reason or however old she was, something drew you to her at that time. You might have been the only person she got to talk with that day and it made her re-think her situation and the fabrics.
A gracious thank you for your time and good luck with your projects is about all you can do. Being rude doesn't solve anything and she may remember you in the future and let you have a chance at it again. If she does, you might ask her to be sure to have sorted out anything she wants to keep ahead of time so you don't get your hopes up.
Your husband was generous to sit and wait for you ... perhaps being at that location for that amount of time saved you from being in the wrong place at the wrong time avoiding a possible disaster. Better to think good of this experience and move along.
Merry Christmas and Peace on Earth...Goodwill to Men