I have a new Samsung S4 and have put a 3 Contract sim in, it keeps telling me my sim is not Verizon?

[AC Question]

I have a new samsung s4 and have put a 3 Contract sim in, it keeps telling me my sim is not verizon.

My internet works at home with my sky broadband but my mobile data on the 3 network will not connect when I am out .... How do I solve this problem ???