I have the Polish version of your name (a short form)
People have called me the wrong name all of my life, even friends can't pronounce it correctly.
Some people seem to be 'tone deaf' when it comes to repeating back a pronunciation, especially if they've read the name first, but to write it incorrectly in emails, etc, is surely just laziness?
It's not quite the same issue, but I do feel your pain a little, op.