Unsafe thug debt collection for money not owed. TSI Transworld Systems Inc; 1105 Schrock Road, Suite 300; Columbus. OH 43229. They sent out a collection notice for an invoice I paid. Horrible reviews online about this company and numerous other people who they have har**sed. Their return mailing address is P.O. Box 15618 Wilmington DE 19850. This is a fraudulent company.