Try this:
1. Go to the Facetime App
2. Press Contacts
3. Click the contact you want to delete
4. In the top right corner, there will be a little button that says edit, click it
5. Scroll all the way down to the bottom of the page
6. In white letters with a red background, it should say delete contact
7. Click delete contact
8. It will say delete contact, or cancel, click delete contact
9. Repeat with any other contacts you want to delete
Please let us know if that works.