Perma ban

Sorry if my English is not good :) It's also my first Discussion i make so i dont know if Miscellaneous is the right place to post it.

My question is when can people be permanent banned?

Today i was playing ranked, and in the game lobby i was Summoner 4, and as i say in every game hi (choose role) mid. But the guy in Summoner 2 said Sry me mid, and of course i respect pick order so i said im going supp then. When it was his turn he instalocked and of course the enemy team chose . The game started fine even though he didn't farm that good only throwing her Q. When had 30 cs only had 7cs. also made that big mistake of attacking a level 6 even thought was only level 4, which gave FIRST BLOOD. But did learned from that mistake??? NO she didn't. She attacked 2 more time which gave her KILLING SPREE in under 8 min. When we told her to stop feeding she was like :Sry guys 1K ping, and then disconnected so we had to surrender in 20 min. Of course i reported her after the game, but will that permanent ban her? If not then back to my question at the top.