I saw o2 doing £10 for 21 GB Data allowance, but when I topped £10 I got only 8 GB Data !

[Reshma]

I saw o2 doing £10 for 21 GB Data allowance, but when I topped £10 I got only 8 GB Data !
can you please help me to allocate the additional data allowance for me. 
thx 

[Enlli]

We can't here as this is a customer to customer Community 

Contact O2 on 4445

[pgn]

And more info here @Reshma 

https://www.o2.co.uk/termsandconditions/rewards/more-data-same-price-big-bundles-rolling-plan

[Oxonian]

There is quite a bit of information @Reshma in this thread :- 

1OGB Extra Free! - O2 Community

https://community.o2.co.uk/t5/Discussions-Feedback/1OGB-Extra-Free/td-p/1747607