Exorbitant annual increase and complete lack of explanation

My home-contents insurance policy with Hollard was taken over by Dotsure this past year. On the annual renewal I got a notice that my premium was going up by 18%! I have not received a single clear answer as to the need for this huge increase despite over 5 emails and at least three phone calls. Some of my emails have not been responded to at all. Multiple promises have been made to call me back and I'm still waiting to get a decent answer since raising this issue first on the 18th October.

Don't be fooled by an initial low premium if Dotsure are going to hike your premiums 18% yearly and not even offer any semblance of a reason.