Rescue email problems

I lost my iphone 4s last year and never got it back, recently I got the iphone5s and when i logged in to my icloud with my email that i used on my 4s there was another email account on it (from the person that found my phone and never gave it back) and now i cant access all details because I need to answer security questions and I cant remembre the answers and i could reset the questions with the rescue email but the problem is that the rescue email is not mine. what should i do?