What is the best way to ban a user through a telegram bot?

Question

Python

Hello!
There is a problem. I need help in implementing a ban/kick of a person who has run out of a package through a telegram bot.
Let's say there is a person who bought some package from a bot, and then the validity period expired and you need to restrict the person's access to the bot's information, let's say that when you click on the button, he would not be given information, but wrote that you need to connect the package.
I think to do this by adding a person to the blacklist, how best to identify the user and what identifier to ban? I thought to do it via chat.id.
Where can I get the chat user ID?
How it is better to implement this system (without DB)? Maybe someone did something similar