I can identify with your daughter. At 15 I would never had said anything, and at 31, I still let things slide half the time. But I'm learning. I'm sure that if you do nothing, your daughter will learn on her own.
But I'll also tell you, one time in college I bought a dress that fell apart after three or four washings. (I didn't' know about superior quality handmade clothing back then. ) I hadn't kept the receipt, and there was no way I was going to take it back in. I was rooming with my grandmother that year, and when she found out, she encouraged me to take it back. I wasn't confident in that, since I didn't have the receipt, and so she offered to do it for me. No big deal, no blaming anything on the store, no making me feel dumb; she just did it matter-of-factly. She came back that night with about 75% of what I had paid for it. She said the store stood behind their product, but the dress was on sale, so without a receipt, they had to give me the sale price. That was a great lesson for me...I got to see how a mature adult handled the problem, and my grandma let me know that I deserved the quality I had paid for. Not because I was so special, but because a consumer should get what they pay for and hold retailers accountable for what they sell.
This is one of those lucky parenting situations that is low-stakes AND will teach a lesson either way you handle it--letting your daughter figure it out like an adult or dealing with it yourself to model to her how an adult would handle it. Good luck!