HOW CAN I FIX THIS SITUATION?

Hi, im 13 years old. So, I have a facebook, and people know im a big black ops fan. There was a fake facebook profile created for Pentagon Thief (a character in black ops for those of u guys who dont know). He started mentioning me in his posts and how im his friend. this caused people to think I made the fake account. people are becoming rude to me at school for making the account. I try to convince them its not me but of course, like any other immature teen, they only belive what they want. I reported the person and said to him on his wall "I reported you for a fake account and making people har me, and if you dont delete your account, i will go further." but people responded saying i was just talking to myself. WHAT DO I DO? i'm being bullied for this.