There have been messages from users who cannot refill on the app or website - If it's a Data Unavailable issue on the app then you should refill on the website by clicking here for airtime refills and here for Bank card refills - Make sure you're signed in on the website to access those pages.
There is a third refill option. You can refill by making a transfer or deposit to:
OKADA BOOKS LTD
Then send a whatsapp message to +2348167247508 to refill you immediately. Your payment will be confirmed and you will be refilled