Salted Correspondences
Let stones lie as they were.
If the above contact methods do not work simply write your letter on a piece of salted paper and hide it under a stone containing no ferrous metal.
I will find it.
The Thousand Year Old Vampire has a beautiful conceptional system of Memories, Experiences, Marks, Diaries and Resources, with which to remark upon the travails of millennia-old vampires.
...Oh, and of how the legal troubles of people past remain the same as ours now:
"...I am a poor knight swindled out of my inheritance."