I bought a second and Xbox 360 and the seller don't know the password how can I get it

You would need to contact support and they can help you reset it.
http://support.xbox.com/contact-us

You should not post your number on a public forum.

Exactly I don't know what's his Xbox Live account. I'm only able to point person as a seller plus I can get login and password from one of sold accounts (but it's not his acc, he only set password to that acc via www site probably).

I've recently purchased a used xbox 360. The seller didn't mention that they had parental lock set and didn't offer the password or reset the settings. Can I get rid of the lock so that I can do a factory reset?

Hi,Kaleb, I'm Luis a Xbox user just like you. Thanks for reaching out us here.

In these type of cases, the only way to sort this out then is by going to the log in page with a secondary email and once there select “forgot password.” Choosing the “forgot password” option will send you the link to a form . You will need to fill it out and wait for Microsoft to contact you and try to help regain access to theaccount,

Here are the detailed instructions and tips to fill the form

https://support.microsoft.com/en-us/account-bil...

Hi there Corban, my name is Gerardo, and I'm an Xbox player, just like you. I'll be happy to assist you with any questions or concerns you may have.

Just to confirm and better understand the situation, I would appreciate it if you could answer the following question:

Do you play Fortnite on a PC through the Epic Games platform, or do you play on an Xbox console?

I'll be awaiting for your response.

Kind regards,
Gerardo.