"If I could score zero I would rather do…"

If I could score zero I would rather do that.
Our house insurance was transferred to Artsure by a broker a year ago. When the insurance came up for renewal I asked one question, I wanted to know why our contents was lumped together in two categories rather than itemised, because on the schedule there is a list of about 20 subcategories.
All I wanted to know was why the contents was not itemised.
This was interpreted by the broker as - I am underinsured - I did not think any such thing.
The broker asserted that because we have a big house I must own a £3000 watch, I don't.
They have extorted more money out of me by stating they would cancel our insurance if I didn't pay them, by the end of the afternoon another £1100 on top of the £2800, we had already paid. Now they are demanding we install a wired fire alarm system.
We inherited the house; we have very little money.
I feel and friends I have talked to about this situation feel that an assumption has been made that because we live in a big house, we must have expensive things this is not the case, instead of believing that we live modestly, I have been accused of hiding something, surely if I was hiding something that I then tried to claim for I wouldn't get a pay-out anyway.
I feel as I am being bullied into paying for their requirements that I cannot afford and do not want.