I managed to get my account back but a different mobile number is registered

Ok so I made this account years ago before the merging of servers and when Krowaz armor was new. I stopped playing for a very long time and I just managed to log into this account by changing my password because I didnt remember it. Problem is, the mobile phone number is registered to someone in Turkey (I live in Calfornia, USA and I never gave KO my number anyway). This tells me someone hacked into my account and registered their number on it. I want to prevent this person from ever getting on my account again. What can I do?

First you need make ICS OTP to protect your account against hackers. Also it's good you send ticket to cutomer support and request change phone number to your own.