I got banned 3 or 2 times

Depends.

It works like a ladder system rather than "you get X punishments before a perma-ban".

10-game restriction 25-game restriction 14-day ban perma-ban

Each punishment will move you up the ladder. The longer you go without being punished or showing bad behavior the more you move back down the punishment ladder. On the opposite end, if you show extremely poor behavior you can skip steps going up.

If you've recently received a 14-day ban consider yourself on the precipice of the perma-ban for a while. If you've only received chat restrictions it would likely take some extremely poor behavior for you to skip the 14-day ban and hit the perma.