Hacking Account

So, I havent played minecraft in a few months due to being busy with school and went back to play and turned out I was hacked. Looking through my email and discovered a lot had been changed (user, email, pass) I was able to "unhack" my email,

but I cant get back my minecraft. Using a website I found out my username was changed from JennerLoo to Delaxin... But I cant figure out how I could possibly hack it myself, any help?

I tried, but they need a transaction ID and I bought Minecraft back in 2011 so I dont have it anymore.