My answer disappeared for some reason but I don't know why...
The device mangment says that the language of the device is set to the language you chose and the apps will display at the chosen language (if it is supported, otherwise to the next available supported of the list).
The thing is that you are in the Greek community and members also... maybe if you try to re-download it after you set your device in English...
Perhaps because the sim is Greek or Cyprian it goes to Greek community automatically?¿