insurance cancelled for no reason

Standard bank insurance called me few days back and told me that they were underwrttern by a certain company now they are changing to another company, and the policy number is the only thing that is going to change, I had no problem with that later that day when I was checking my emails , I found a policy document, then I went through the document I found that my policy have changed. I called standard bank insurance for clarification, the lady asked me to pot me through to their underwritters, I refused because I did not open my account with them I only opened my account with standard bank insurance, so I asked the agent to ask them on my behalf as I was standard bank customer, the lady said she will email them.

On the 12th of December I have received an email stating that my insurance has been cancelled, unfortunately I do not understand why was it cancelled as they did not call me to explain why my insurance was cancelled