Here are 2 things i found out to make things easier
-If u asked for a password recovery it says "A request for a new password for your PvP.net account (Ign) has been received. Please follow the link below to set a new password," when u got the mail. Just type in the ign in lolking to see if the account is worth hacking.
-If u found a mail that already has username recovery just use the one listed in the email(chances are the account isnt good since someone already looked)
Also if u found a account that doesnt have much rp, always make sure to check the purchase history because u probably have refunds- I got a account that had very little but i refunded the nid skin and the champ and i ended up with 2k rp