What's going on with the "WMG" copyright on YouTube?

Yesterday, I made a video featuring a pile of videos I caught in three dealerships in Renton. Then at home, I re-edit it with the use of three songs I converted into WMA formats. One is from Grover Washington Jr, one is from Michael Buble, and the last is from Dusty Springfield. I mixed all three songs in the video I created and I uploaded it from YouTube. Then, moments later, I received a e-mail from YouTube, then on the following, the audio from my video is muted! It says something about the audio being owned by darn WMG! What the heck is WMG doing with all our hard-worked videos uploaded on YouTube?