Poor Support, Application with bugs
I was double charged several times. First time I got the refund back, the second time I did not. The application has bugs and does not upload all questions after the purchase, so you have to download a separate app. When trying to restore the application with full version, customers are charged even the application had been purchased in past. Wrote to the support, but their attitude was: this is not our business, we are just developers, please contact the seller.