Hi qertyjjj
Thanks for coming back to us here.
What you will need to do is , purchase a £15 top up for your 3GB. Then the £9.99 will then be taken from this. So affectively this will then take up 2/3 of your usage for the 50MB.
I hope this makes sense, if you have any further questions just let me know and we'll be happy to help you further
Thanks
Wayne
eForum Team