It isn't kind of your fault, it is your fault. Gather as much information as possible and contact the police, your ISP, and his ISP. If you need to "hack" his system, do it on your own if you need revenge and to get your money back.
I remember the last time I "hacked" some guys computer, I sent it a trojan that automatically figured out that he stole money from me and auto deposited into my account. <-- That is sarcasm, but you were probably believing it. No, no one will help you do something illegal. Topic is closed.