If you are using an iOS phone and don't have an Android device, you can install the emulator on your computer and download the MyCard APK to access the game and top up with MyCard!
Download and install Nox or BlueStacks emulator. With the above two emulator, you can have an android system on your pc, and install MyCard APK in it.
Nox emulator installation guide
BlueStacks emulator installation guide
After the installation, log in to your Google Play Store account (same as Google account).
Download the MyCard APK and follow the emulator instructions to complete the installation, or drag and drop the apk to the emulator on your computer to start the installation.
After entering the game, you can refer to the below top up guide about how to top up~