Buying account

Hey guys,
I wanted to ask how do I secure my account after buying it from a random person so he can't take it back.

change all details, verify your e-mail to the account and maybe even change the name, delete everybody in the friendlist.

Thats all you can do, he could maybe get it back when he writes a ticket to the support, but there is nothing you can do to avoid it

You can get the Account back, if you can answer all the question from Support.

I do not recommend doing so, the owner can always get his account back in the ways mentioned above.