Caution Purchasing This App

I hate to pick on a specific company selling Android apps, but if an app isn’t working I want to let others know!  I purchased and downloaded the ‘Irregular verbs - English Language Art Grammar App' today from the Amazon Appstore. It doesn’t work on my Lenovo A1 or my phone (LG DoublePlay); I couldn't figure out how to get a refund.  It does work on the first generation Kindle Fire.  If you don’t have a first generation Kindle, I don’t recommend downloading it or probably the 'Irregular Plurals - English Language Art Grammar App'. They may not work on your devices.  I will contact Abitalk this week and see if they can get it working.