Well, that’s why the spring came out. It’s not your fault; it’s because it’s one of the aspects which the failed to copy properly. They can be carefully reinserted, but that’s regarding the original Chinese part. The way to avoid them falling out is to ensure they lift and drop perpendicular to the movement. If they angle then they pop out entirely. The Swiss ones are easy.
You may be best finding Chinese spares if that’s possible. I can offer some real incabloc springs, but they are all from 10 - 12 ligne watches, so not sure if they’d be a bit small.