Ask HN: What to do with plagiarized apps in the App Store?

Does anyone have experience with filing copyright issues with Apple? We found an app called LimeLight on Mac App Store http://apple.co/2eM3Tau and it is using the same design and UI/UI from an earlier version of Polarr v2.0 hosted at http://bit.ly/2fDfqYO (already deprecated).

We reached out the Apple Store through copyright claim and so far we are instructed to resolve this issue with LimeLight's developer directly. However, it seems like the developer has a lawyer in India protecting him and now they're sending us legal documents indicating that they designed the app way earlier than we did and we should not harass them anymore.

We downloaded LimeLight, run through a code analysis and found references to Polarr entities in their source code as well as them possessing the same source code structure as our deprecated Chrome app. Right now, Apple Store is CCed in our conversation chain but has stayed quiet about this.

Frankly, we don't think they're making a lot of money right now but we fear that they will start to copy our latest app versions (see http://bit.ly/2fyVZjk) and release to App Store, eventually jeopardizing our revenue and confuse our brand.

We're a small team so we are wondering what is the best approach to situations like this.