Second Hand Sim City Product Code 'Already been used'

Hi,

So my friend game me a second hand copy of SimCity (2013) recently. When I tried to install it onto my PC, I put in the disc; Installed Origin; Put in the product code and thats where I had the problem.

So when I put the code in it said it was 'Already in use'. Is this because the game is second-hand? 

If so, how can I activate my SimCity in other ways/get a new product key?

Thanks for the help,

Oscar