i don't think my marks have ever worked, how do i get to know? it says if someone i marked dies i find out what they do but i havn't got anyone...

I once tried to mark and was told an old mark remains and i couldn't, i thought i could mark multiple targets over time (overlap of the two days) but apparently not. my mark at the moment is runeboundshade but my scry didn't work as i said earlyer...