Copyright issues

Hey guys so I know I'm still new to the whole editing videos and stuff and I got two comyright issue complaints from Youtube since I used the music from there for my Graduation Video and JT Carter Video. So I might have to mute those or something and redo them by buying all the  on iTunes and putting them back into the video later on. Most likely I might have to take down those videos, and put it back up once I get all the music that matches the songs I used from iTunes. Sorry if you can't view them right now. If you're wondering why you can't, that's probably the problem right now. So sorry for that I'm still new to this ^^'