I don't know the answers to my Apple ID security questions and I want to buy music

Do you have a recovery email set up?

Then try the methods described here in this link:

Apple ID: All about Apple ID security questions

Without a working Recovery email you need to give Apple Support a call - only they will be able to help you. See this webpage on how to contact Apple Support in your country: There are either telephone numbers given or an email form:

Apple ID: Contacting Apple for help with Apple ID account security

Explain, that you need help with an account security problem.

You can also try to email the iTunes Support using this form: https://ssl.apple.com/emea/support/itunes/contact.html