xperia z2 sim not working

[Xperia123]

i have recently bought a xperia z2 from a seller on gum tree and he sold me an xperia z2 which is on EE, i put the EE sim in and it shows the signal but does not let me call or text,  tried giffgaff and 02 and same situation. 

Anyone knows what this mean?

[Thommo]

Dial *#*#7378423#*#* then open Service info then Sim lock - If you see something like [X] text here then the number 0 then it's hard locked - If you see [X] text here 5 then that it how many chances you have to unlock your device and if you see [ ] text here 0 then it is sim unlocked - It's also possible that the seller has possibly sold you a banned device either a contract device that hasn't had the bill paid or it's a lost or stolen device and again has been banned by the networks

[Xperia123]

I'v tried that and on the left hand side they all show [ ] and the right hand side show 0 attempts, any ways i can get that sorted out ?

thanks for your help so far