when does "you are ineligible to earn rewards because of previous somehing" go away

Two days before I got permabanned.

This board will most likely answer any questions related to this:

http://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/57wOcrmh-if-you-are-ineligible-for-hextech-loot-read-here-for-info-on-becoming-eligible-again

It took me half a year, boy was I toxic lol

For me it took 4 months for it to go away. The funny thing is I was doing the exact some thing I was banned for during those 4 months and constantly telling Riot that I was still doing the thing they banned me for. Now I'm considered "reformed" by their system and getting loot.

Might be a different case for you, but odds are you're going to get that loo without having to change a single thing. Riot's not going to do anything even when you tell them that you're still doing it. (I would know. They pull up my logs saying that I'm still doing the thing I was banned for after I told them I am now "reformed" and getting loot. Nothing's happening)