I've had similar experiences as a seller on eBay: when a buyer reports you they react in favour of the buyer because buyers make their business model work.
I suspect it's the same here, that Apple have received some sort of complaint about the iOS app (given that the macOS app is unaffected) and the automatic "guilty until proven innocent" system has been activated. And sadly the only thing to do is wait for it to finish. It could be something like waiting 60 or 90 days without any further complaints of the same nature. You could hope for intervention by a sympathetic App Store employee or rep, but I don't know how likely that will be.
To add insult to injury there is also the fact that this is an open source app and dishonest people are cloning it and selling it, and Apple are slow to take them down if they do at all.