Lost mojang/minecraft account. Is there any way i can get it back?

I bought minecraft a long time ago, probably 4 or so years ago. I've checked every email i've had since then and i can't find the transaction ID in any of my emails. I can't log into mojang or minecraft with my username or password that i have written down and customer support hasn't been very helpful. Is there ANY way i could possibly get my account back, or is it a lost cause?

Added (1). oh also when i try to change my password, i put in my username and it says my account has migrated. And when i try to reset my email it asks me for the email on my account still?

I suggest going to the website (Minecraft.Net) then go to "Help" then click "Minecraft Accounts" then look through the choices, I've had the same problem and it helped! I really hope you get your account back! If you'd like I can try to help you too but goodluck!