Pulling teeth is much easier, less painful, and possibly less bloody than trying to get cash back from a Chinese merchant.
Try for the 2nd repair. Albeit, they will try to charge you another 200 to 300 rmb for yet another screen/visualizer part. Here you will have to be very demanding and willing to make a scene. Bringing a friend(s) along wouldn't hurt.
If you went to the shop the next day after your faulty repair, you should have a good chance at obtaining a 2nd repair for free. If the problem didn't fully manifest itself till several days later or you waited to complain, then this is much more problematic. Essentially, this now becomes a tug-of-war between how willing you are to make a scene and the Chinese shop owner's obstinacy.
In Shenzhen, the repair shop I frequent for my iPhone would most likely take a 2nd look at it for free. They would repair it without charging me for another expensive part if I start and continue to badger/scream at them they used a crap/wrong part to start with. However, I speak fluent Chinese and have used this shop more than once.
As a practice, I wouldn't have my smartphone or Apple products repaired in Kunming except at an authorized repair shop or the big chains mentioned above. Of course those places all charge considerably more.