I got my perma ban after a game suddenly as well for the same reason you mentioned. I suspected two things for my ban:
-
90% of my games have been Braum after I picked it up in my recent trip to Korea. My KDA for Braum got enormously high for the past month, possibly raising suspicions. Most of my games have been 4-5 man ques also, which gives better strategy and communications that have led to a better KDA and win rate as well.
-
I do use Razer Cortex to shut off other programs but I'm not sure if Riot considers that as a 3rd party program.
So I tried to dispute my case to riot, they sent the same automated message like you received. I tried appealing again and came this very rude response on how there is "no error" in their investigation.
"Hey again,
I am a player behavior specialist mentioned by XXX. This isn't about playing well. We only take this sort of action when we have conclusive evidence and based on my personal review coupled with the review of our team here, there is no error. If there are no other questions or concerns, I'll have to consider this matter resolved.
If you'd like to discuss anything else let me know, otherwise the ticket will be closed."
Unfortunately, I don't think you will get your account back as well.