Reclaiming premiums for drain cover

Hopefully someone can help!
We had insurance for our drains for a couple of years. We finally needed to use it for an emergency (drains completely blocked, waste all over the path and couldn't use sinks or toilets during half term!).
We called on a Sunday and they said they'd get someone out to us that night - they cancelled at short notice because a previous job over-ran.
We re-arranged for Tuesday afternoon - they cancelled again at short notice because a previous job over-ran (my wife lost 3 hours work and is hourly paid).
They offered us another appointment on the Wednesday, but we had lost faith and cancelled our policy, raised a complaint for a refund and booked someone else to clear the drains.
They're offering £100 compensation plus the cost of getting the drains cleared. This doesn't cover my wife's lost earnings, let alone the inconvenience of having to drive kids over to the grand parents as they couldn't stay in the house with no toilets.
I want to reclaim all premiums paid as they failed to offer the service that I paid in to - am I right to claim this or should I just accept the £100 and move on?
Thanks!