Disgusted and Dissatisfied

I bought a laptop a few years ago and took out insurance for it, I was very satisfied with it's performance. The problem started a few weeks ago when I took it out then I noticed, the laptop is disfigured because the battery is swollen, it is a build in battery. Unfortunately the warranty of the laptop is finished but because I took out insurance for accidental damage I honestly thought that I would be covered, but my claim was declined without a valid reason. I just mentioned that the battery is swollen, I am not a technician to tell what could be the cause of it. I remember once a bit of water fell onto it but it was still functioning. My claim was just declined without even a technician assessing the laptop. I will never recommend this insurance to anyone and this complain will be investigated by the ombudsman.