Five Cities in the South Island

When I arrived at the car rental company, they told me I hadn't purchased insurance and suggested I ask the rental platform about it. When I contacted the rental platform, they told me to ask the car rental company, as they were not sure. I went back to the car rental desk, and the representative said my order showed no insurance and advised me to spend around 290 to get one. Being abroad with no other option and not wanting to risk any issues, I spent 300 NZD for comprehensive insurance plus a full tank of gas. So is this the car rental company's issue or the rental platform's issue? I'm not sure. Anyway, I drove for seven days without any problems. The roads were great and driving carefully was no issue at all!