Former employee has 'findmyiphone' turn on on their itunes account and now I can't restore the phone

Our company purchases phones for staff, a staff member has left (on not such good terms) but still has the iphone with 'find my iphone' within their itunes account. I understand this is a security feature but I can't restore the iphone for someone else to use it.

I'm really not sure what to do, i can't contact the former employee but my company owns the phone. Has anyone else experienced this issue? I really don't know where to go for help!

Many Thanks