Alux app purchases and subscriptions are managed only via Apple App Store (for iOS) and Google Play Store (for Android).
How to request a refund:
Apple App Store: https://support.apple.com/en-us/HT204084
Google Play: https://support.google.com/googleplay/answer/2479637?hl=en
How to cancel your subscription:
Apple App Store: https://support.apple.com/en-us/HT202039
Google Play: https://support.google.com/googleplay/answer/7018481