Perma Ban

So I recently got permabanned, however, I don't believe it's my fault at all. I myself wasn't on my main account at the time, in fact, I wasn't even playing league. Someone got on my account and played on it, if you need proof you can look at my match history and it shows 2 champions I have never played before in the past. Lucian, and Gnar. I checked my blitz and it showed a random username. Blitz usually does this when someone goes on your account anonymously. They did believe me that I was not on my account on the time (really appreciate that riot)

However, they still did not appeal to my penalty. They said because you did not secure your account enough, first and for most I would like to say how is this my fault? You provide me with a security form that I did fill out and a 3 step verification that is not mandatory, if it is bannable that if someone goes through the 2nd step verification and u don't have a 3rd step verification then why isn't it mandatory? I did what I could with what riot games provided me at the time and used it to the best of my ability. I secured my account based on riot games needs and regulations and still, they blame me it's my fault? And yes, I myself was toxic in the past and they gave me one last chance.

Technically it's there fault for not securing my account hard enough AND on top of that, they permaban me for it?

What do you guys think? Do you believe this is permaban worthy?