Change mobile data plan

[ann42]

i currently have the 3gb for £7 a month but i saw the 40gb for £12 black friday deal. but when going to change to it, it comes up with it for £24 a month whereas it should be £12. what do i do?

[GD1]

@ann42  Those deals tend to be for new sims& number and not upgrades to an existing sim/data package.