Have a look at this related article and how to proceed:
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Report a problem with an app or In-App Purchase
You can also report problematic apps at reportaproblem.apple.com. Apple will investigate and remove any apps that are found to be malicious.
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Across Apple, there are a number of experts — from App Review to Trust & Safety teams — that work around the clock to detect, investigate, and prevent malicious activity on the App Store before it can reach users.
In addition to the work of these teams, there are resources, such as an app’s Privacy Nutrition Label, user ratings and reviews, and age ratings, to help you make informed decisions on which apps to download.
Report suspicious app activity
If you suspect suspicious activity in an app that you downloaded from the App Store, report it at reportaproblem.apple.com. Apple investigates and takes swift action accordingly.
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copied from: Maintaining a safe App Store experience - Apple Support