The only thing that I have found to remove ink f/ leather is hairspray. Use spray from a pump type container (not aerosol) and blot with a dry cloth or papertowel. If you rub instead of blot it will spread the stain.
Be sure to test the hairspray first on an inconspicious area.
Once the stain is gone use a damp cloth (just water) to blot away the excess hairspray.