It's difficult to cancel my cell phone insurance

I had bought a cellphone at me price and insured it. Now I want to cancel it. I called them three months ago to cancel it. The man I spoke to said it's canceled. To MY surprise it still reflect on my statement. It's so difficult to cancel you can't get hold of them at all. You call them you reach a dead end EVERY TIME . I've been insured with them for 3 years now. I want to cancel 😞.