Family Protection Plan not cancelled

I settled my Acc last year and forgot about the family protection plan I had with them. I received a very rude call at 7pm while having dinner with my family in Feb from a collections agent for Dec and Jan amounts that accumulated from the protection plan so I decided to cancel it. That was on the 10th March 2019. When I requested a ref for the cancellation, the agent told me they don’t have references and I must use her name. What nonsense. The family protection plan is still appearing on my statement. I called the queries line to enquirer about this and I was told I have to call Hollard and no ref for the call again. I joined the protection plan at an Ackermans store, Bt now I must call Hollard. I want this sorted