hacked account!

last week my account was hacked. i have not played league of legends in the new year of 2020 the last time i played was on new years. i changed my password a few days ago because i noticed someone was using my account and messaging someone on my leagues, i found out from someone telling me and asking me why i was telling them they are annoying. they played a few games on my account and the last i seen i thought i put a stop to it once i changed my password. i am finally home and login with my computer and it is saying there was 3rd party software use on my account and my account is now permanently banned? id like this to be investigated please. maybe check the IP address of witch my account has been used from. id really like to know what happened as this has caused me panic. i am a loyal and rule abiding player of leagues and i would like my account back and protected against unauthorized use and to have this matter looked into please. last i know unauthorized use of game play with zyra and oriana and senna but it caused quiet a panic and thought i resolved this issue with a password change until i login and got a surprise my account is permanently banned and blocked! unauthorized use of my account on the 13th and 14th. any suggestions? ive sent a ticket to riot! i noticed this in match history when i noticed my account was seemengly online to my leagues friends and i was messaged in real life and changed my password! please help!