Very angry customer

I work in a Mall, so one of the guy's selling insurance from Martin's funeral comes and sells the policy to me him name is Tokelo and his manager is Lindon from dobsonvile branch. The policy is R320 and he said if I have any problem I should inform him. Then on the 19 I sent him a message saying I've changed my mind I no longer want this policy, he says ok I'll send you the cancellation documents. Then I want, come month end they debit my account and I write a message to the guy all he does is not reply, no refund. His no longer answering my messages and I'm very angry cause Martin's funeral and it's employees take advantage. How can I cancel and still they debit. I wanna tell people not to entertain staff from Martin's funeral, they are full of lies.