It looks like someone else might be using your account

The title comes up when I try to log into my ****@hotmail.co.uk account, I have tried going through the steps and filling in the form to try prove it is mine but whoever has my account has changed everything (it is all in Japanese). So what I am trying to say is I have tried filling out the form about 5-6 times and every time it hasn't been successful and there is no other alternative. So after giving up trying I ring customer support after about 20 minutes of being bounced around I get to talk to someone, they tell me that there is no one over that phone that can deal with my request and recommended me to come here... Now I just want to prove that it is my account and someone be able to get me it back and not tell me anything I already know. I have had that account for many year and I have important emails going to that account, is there anyone that can help me get it back pretty swiftish?

Ps I am using my mothers account to talk on this as I can not log into mine.