Sorry to hear about the ink stains - tough to deal with!!
Do try calling the manufacturer for info - if you can get the 'Material Safety Data Sheet' (MSDS) for the product from the manufacturer you might be able to figure out what would be effective to eliminate it. The MSDS is a document that contains information on the chemical nature of the product (what it is made up of) and its physical and chemical properties - could also include info on clean up in case of a spill. The manufacturer has this info as it is required by law to have in in the factory - whether they will share their "secret ingredients" is another story. Haha - back to chemistry class!
I have also had success with rubbing alcohol (isopropyl alcohol) on permanent marker.
Be very careful with Synthropol - it is an extremely strong chemical.
Good luck with this and do post how you do - Hopefully some of the suggestions will work for you
