Just bought a brand new ipad air 32gb with wifi and cellular, never been on ANY networks what so ever. I purchased a nano sim for the ipad air its a t-mobile one. I inserted it into the ipad air, it reads that its t-mobile. But how do i top it up? or get some type of data plan i've looked all over the internet and i don't have the slightest what to do. There was also articles stating i could get 200mb per month for free, thats one of the main reasons i bought the cellular version in the first place. PS i live in the united kingdom.