Adding of insurance policies without my knowledge

I opened account with Jet around April May 2017. I was amazed by the instalment not decreasing though sometimes I was paying more. In September 2017 I enquired about this at the store they checked and find out that I have policies which I did not apply for. They said they will cancel them at my request. In February 2018 I paid my instalment and my balance was +- R1000. In March I went to Jet to buy something worth R50 only to find out that I do not have credit, I have to pay R500 first because my balance is now R1500. I asked them to check whether policies have cancelled, they checked and find out that I have 3 policies and Jet club. Now I'm very upset about this, paying for extras I did not ask for and I ask them to cancel and they did not. Last time I tried to cancel 05-03-2018 the insurance companies don't pick up the calls when they call them at the store. They said they are going to try to cancel automatically, I must come back to check whether the cancellation process has been successful.