Default [HELP] how can i learn my phone's root date?

Hello people, i bought a lg g2 on a web site and they sent me a used and rooted phone. I need to leant it to give it to justice as a proof.
I guess we can learn by checking the secret code 3845#*802# and going LG RCT ➡ LG RCT CHECK but my status is Disabled. How can i change it or are there any other way to learn the root date?