Insurance and company

I bought a stove that has a glass on top, fridge and a washing machine from them late 2018. I added an insurance that covers me for three years. In less than a month that I bought the furniture, when I switched on the stove, the glass broked. I called them to come and fix it, and come and fix it. In less than one year I settled the acc. So, now the same thing has happened, they come and said, it's a customer negligence and they didn't fix it. So, my question is that, what was the reason for me to pay three months insurance, if its not helping me at all?