Dear Mr. Jack,
We wish to inform you of our decision to cancel our policy with your company. This is because of the many unpleasant encounters we have had with your claims department.
Over the past two years, we made three claims of which not even one has been settled. It is always some excuse like misplacement of files, unfinished reports or technical errors for the delay. It appears that your company has no intention of paying. So I am taking my business elsewhere. I do not want to continue the hassle of dealing with a brick wall. So please cancel my policy and refund whatever premiums that are due to me.