What was I supposed to send off with my xbox 360?

Ok, I went to the ups store today with my xbox 360 and I mailed it off to somewhere in mesquite Texas, however, I didn't send anything else. Was I supposed to package the power cords and the av cables also? I asked the man that, but he pursuaded my dad to not send it in, since my dad thought it would cost more. Will they send it right back to me without fixing it because I didn't send that in? Or will they just fix/replace it anyway?