How does it take for a player to get banned after reporting?

Hi everyone, last week on the 20th I reported a player for ninja looting in ICC 25, it was an obvious case of ninja looting I uploaded the video to youtube of the entire run and ALL the details and timestamps etc. I opened a ticket in-game with the link to the video and describing what had happened. A few days later I got the usual reply "thank you for reporting we will investigate"...
Just so you have an idea of what happened, when the leader rolled the caster ring from GS a priest (rolling for disco) won the roll fair and square. The co-lead was 2nd roll (he was mage) and the leader himself was the 3rd highest roll (boomie).
The leader than said this is not for dico (it's BiS for disco btw) and refused to give the item to the priest.
The leader than left the group keeping the item, I asked the priest if he got the item and he confirmed that indeed the leader did NOT give him the item.
Later I check armory and the leader is using the ring he had ninja.
Today, 6 days later this player is still not banned.
So my question is how long does it usually take between the report and the ban?

A ninja scenario can't be more obvious than this and the guy is still playing. I just would like to know if there is still hope for him to get banned and also it would be good to know if it's even worth reporting if nothing is being done. The process of uploading the video and doing the report etc. take quite some time and effort and seeing that there are no consequences for the ninja it's a bit frustrating that I wasted my time doing all this for nothing...

Any thoughts would be appreciated.

Thank you!