Had the same thing last year with my mum's plumbing/water pipes insurance. The well-known company soon lowered it to the previous year's amount after a few minutes haggling on the phone.
Well, it would have been only a few minutes if they hadn't needed to get my mum, 120 miles away, on the phone at the same time to give them her consent.
Same thing with her phone/broadband a month ago. Mum didn't know that the deal she had been on (all previously dealt with by my late dad) had ended until the bill shot up 33%.
I checked some other companies' deals and, armed with their prices, contacted her provider, who soon offered a new contract on more or less the old price.
I hate having to do it, but it seems to be the only way to avoid being ripped off!