Girls Love Girls Necklace

I got this along with two other necklaces and they’re all gorgeous. The only issue is that this necklace I wore every day and it started to tarnish in less than a month. I thought it was supposed to be gold filled but it must not be. I was super disappointed because I love the necklace and now I can’t wear it cuz it makes my skin itch. The other two did not tarnish yet but I only wear them on special occasions.