Kaktus Dobíječka is an Android app designed to notify users of the start of a Kaktus promotion. The app doubles the amount of credit recharged, making it a valuable tool for Kaktus users. However, users may encounter issues with notifications not being received. To resolve this, users can check the app's notification settings, ensure that the app is not listed under unused applications, and enable Kaktus Dobíječka in any task killers or battery savers. If all else fails, users can contact the developer for assistance via Google Play feedback or email. It's important to note that Kaktus Dobíječka is not an official app from Kaktus (T-Mobile CZ a.s.), and users should use it at their own risk. The app's source code is available on GitHub.