After the free trial period expired, I have tried to subscribe to keep the app going. However, when trying to bill to my phone's account, I keep getting an error message. Why does this message keep appearing?
This is a free application. It's not necessary to buy it because it's ad supported. You can use it for as long as you want but from time to time ads will be displayed on screen. However, if you have issues with your purchase, check your credit card because it may be blocked or it's lacking necessary funds.
