When I said "its not that hard" I meant:
With deep directories warn the user that it will have an impact in terms of performance, and encourage her to sync specific folders instead of her root directory.
Just do what other applications like Nebulous Lite does, its not that hard, if a free app offers it, why not a paid one like yours?
If App Store had a refund policy like Google Play I would have already asked for a refund.
Customer support service by UserEcho