(Sorry for hijacking DTN's post, but I didn't think I had enough to say to justify my own response to the thread at this time)
I recommend continuously replying until you get a non-canned response.
If the response looks like it is a canned templated response, reply saying "I want a support specialist to perform a manual review of my compromised account. I do not want another template response." Do this until they answer with a thorough answer as to why they believe your account is not compromised.
Furthermore, make sure you are making this ticket under an email/account that is separate from the email and account that was compromised. Riot will not entertain compromised account support tickets that are from an email associated with the account, whether now or previously.
Best of luck!