I canceled netflix and received the confirmation via email. How can I delete my data from the account now?

Hopefully I don't have to pay now because I quit. For security, I want to delete my data there.

What for? More effort than anything else. If you quit, you quit. If not, deletion won't do you any good. They're not stupid.

But when hackers come my data is there!

Call customer service.

Read in the terms and conditions how long your data will be kept / how you can have them deleted.

Otherwise, you might have had to adjust / change something before the teasing.