Vodacom Insurance, impossible to cancel

Since my mother upgraded her phone earlier this year we cancelled the insurance on the phone, due to Samsung giving a better insurance plan. Every month the insurance just get added again to the bill and she has to phone again and cancel it again. Its been 3times cancelled now and each time it's just added again. The insurance guys says they don't know why vodacom keeps adding it to the bill. The insurance money was now deducted from her account and she is furious about this. How is this possible?!! Please attend to this matter ASAP, as she wants her money back, not credited to her account and I think a proper reason for this and a big apology is needed.