Help!! disturbing prank calls!

someone's been calling my phone restricted (blocked) from 7pm til 3 am, i don't know who it is............when i pick up the phone i hear 1 of beethoven's symphonys..it's creepy...............................ok playing pranks or whatever at night time is o.k,but at 3 in the morning??? waking me up out of my sleep...................................… know what's going on?? or do anyone know what these pranksters are trying to prove????