Cancelled insurance Debit order still dedcuted

on the 5Th of march i called the company to cancel my insurance,they said someone would call me,then on the 16th they debited my account which had no funds and caused R350 in return debit order charges and i called through a gentleman said i must send him the statement and a refund would be done,i called through today and the lady said that it was not cancelled on the 5th and that the refund cannot take place.I would suggest no one use their service rather go with another company due to bad service and *********** staff