Account hacked!

These days, someone stole my battlenet account and changed my data. I tried to make two tickets from different accounts and I managed to block the account with the help of the Blizzard team, but now I don’t know what to do or how to enter live chat with someone from the Blizzard team

You can’t. Blizzard does not provide this kind of support. Online tickets are the only thing that can help you.
Also this forum category is only for web API discussion: Posting Guidelines: READ FIRST

Ok, but I received an email from the blizzard team in which he says to contact them on live chat.

Live chat IS an option for some account and Billing issues. Right now it is only available a limited amount of time per day.

To check and see if it is up you would go to Support > Contact Support > use the options they told you to use (I hope).

you have to select the right menu options at the right time of day.

The WoW Customer Support Forum tends to have live folks during the middle of the day who can help guide you through the proper system.