i dont remember answers to security questions and cant buy music, how can i solve this

Frequently asked questions about Apple ID - http://support.apple.com/kb/HE37 --> Can I change the answers to the security questions for my Apple ID? --> Yes. You can change the answers to the security questions provided when you originally signed up for your Apple ID. Go to My Apple ID (http://appleid.apple.com/) and click Manage your account.

Forgotten security questions - https://discussions.apple.com/thread/3955839?answerId=18402551022#18402551022 and https://discussions.apple.com/thread/4022217

More involved forgotten question issues - https://discussions.apple.com/thread/3961813

Kappy 09/2012 post about security questions - https://discussions.apple.com/thread/4295386?answerId=19569468022#19569468022

John Galt's tips (09&11/2012) - https://discussions.apple.com/thread/4370293?answerId=19809294022#19809294022 and https://discussions.apple.com/thread/4489810?answerId=20229239022#20229239022

If none of the above work, contact iTunes Support at http://www.apple.com/support/itunes/contact/ and follow the instructions to report the issue to the iTunes Store.