The Aussie does speak the truth.
You are RENTING the account from Blizzard. You are RENTING the account to play the game ($15/mo subscription, I have no idea how much that is in Euros.). It is impossible to sue Blizzard for banning your access to an account that you are RENTING from them. It's like eating a pizza and then sueing the resturant for makign you pay for their pizza. It just does not work.