Nostalrius Begins - Quality wow vanilla realm (1.12)

Hello, GM, yesterday evening, I was still playing the game, but dropped, then login the game told me account was banned, I want to know why. Please help me, thank you.

account:Virile
serve:PVP

I swear I've never done that, and I've always followed the rules of the game.
Recently when I play the game, "charge" and "intercept" skills often lead to dropped game, I think the only because the network. I assure you that I have never used any cheat software.