question: About Google Play Store in-app purchases for ExpressVPN
answer: 
  ExpressVPN subscriptions are now available for purchase via the Google Play Store.
  
  Jump to…
  
  General details about Play Store in-app subscriptions
  Change subscription plans
  Update billing information or payment methods
  Resolve payment issues
  Resubscribe to a Play Store subscription after cancelling
  30-day money-back guarantee (refunds)
  Cancel a free trial or subscription