To enable Push Notifications in Walla App for your iPhone, please use the following steps.
Enable Push Notifications on the Walla App
Within Walla, go to Account
Choose Notification Settings
Turn on the toggle for Push Notifications
Select Save
You will want to double check your phone Settings as well to make sure Allow Notifications is enabled:
From your phone's Home screen select Settings
Scroll down your Settings and select Walla App
Select the Walla App
Choose Notifications
Turn on the Allow Notifications toggle