I need help ASAP

My account was suspended 2 weeks ago because of toxicity, thing is, I didn't even play when the account was banned, someone else logged into my account and decided to flame in literally every sentence sent on that game.

Iv'e been trying to "recover" my account but I can't do anything since I still have access to it, they (Riot support staff) won't even send me the IP address logs so I could see who's IP was logged on the day I received the suspension.

Three days ago one of Riot's support members decided to start the whole account recovery process via another mail to see how much I know about my account regarding champion purchases, refunds, creation and such.. but unfortunately it ended up as my fault since I "didn't protect my account well enough" as they say.

I'm not saying the staff's been stubborn or unhelpful, most the ticket was just auto responses with slivers (<--- notice this doesn't say silver) of human communication signs and Iv'e tried my best in trying to reach their hearts but it was all in vain.

Yesterday the suspension wore off and the player who had caused my account all this suffering still has access to my account... I don't remember my mail address and when I try to look it up in the site under "settings" it says I need to enter the verification code that was sent to that mail so I could continue further. ;-;

Has anyone ever experienced this before and if so could you help me in answering these few questions; 1- Is it possible to temporarily block the account until I figure out what the mail address is? 2- Do you have any tips as to what I can do in order to convince Riot that I wasn't the one playing on that day?

Thanks to anyone who took a few minutes of his time to help me, I really appreciate it.