@Riot - Third Party Program Ban???

Is overwolf illegal, even though its just an informative app, that is used by a large amount of people in ranked play? I read up on the app before I tried it, which I didnt enjoy it as it made my computer run sluggish, but when i was reading on it, there was a lot of players vouching for it, streamers and youtubers in the community all sponsored it as a legitimate plugin. That is the only thing i have ever used for league and even then it was a long time ago. I submitted a ticket for it, but I genuinely dont understand, the account that was banned is quite a few years old and has a lot of money on it so i wouldnt ever be dumb enough to risk losing the account with something as stupid as a hack. Can I please get some responses about this?

UPDATE!!!!!!!!!! I just logged into OP.GG and there are three games played on 10/09/2019 that were not me, and i havent given my account information out. I have updated the ticket and hopefully they investigate it and see who logged and played on my account.

After 15 Hours, still havent gotten back anything from Riot Support. Can I please have some help with my ticket?

UPDATE! Issue has been resolved, my account is unbanned, they detected an unauthorized user. They said he was most likely cheating.