Got smarty for mobile internet but not working please help

Hi all, I've got a smarty Internet data only sim (£9 per month)

I've installed it in unlocked mobile phone and want to use it for chromebook to connect to the Internet. 

Previously I was using my personal mobile but I wanted a dedicated alternate leaving my data on my phone alone. 

So I've installed the sim, and app, sim is recognised but it won't connect to the Internet either as a hotspot or through chrome on the mobile. 

Can someone help please