Fulcrum Collections and Oversurance - Stop*****ing

These two companies are *****ing money from my account each month R99-99 each month reference number changes one day it's Bizo, then Telecon, Medhelp etc. Nedbank gave me Fulcrum Collections number. I phoned them. They told me it is for Oversurance ***. I called them but no answer. These are not authorised debit orders and they need to stop!