Unlimited data

[Dat]

How do I get unlimited data for a month 

[pgn]

If you are on an O2 Refresh tariff, Guide: How does O2 Refresh work? @Dat - purchased directly from O2 when you took out your contract, then this may help you: 

https://www.o2.co.uk/refresh/flexible-tariffs

Otherwise you are into a series of (expensive, relatively) bolt ons - https://www.o2.co.uk/shop/all-tariffs/bolt-ons

Hope that helps!