Unsolicited use of my name / email address

Someone has been using My name, and email address, to order from Mannatech. I have NEVER ordered anything from them and have never been in contact with them. I have now been struggling for about 6 months to get my records removed from their database. The person that is using my name and email, resides in Lichtenburg, I live in NELSPRUIT. Despite various mails, threats, unsubscribing etc, Mannatech still keeps contacting me. This is now a POPIA infringement!