Unfairly rejected my claim

Regent insurance has rejected my claim because they claim that I failed to desclose that I had a claim in 2014. I don't know how I forgot how to disclose such information to them whereas I had disclosed it to my previous insurance Dial Direct which i used from the 2015 till the time I took out the policy with Regent Insurance on the 1st of October 2017. Besides that, on the 28th of July 2017, I noticed that the type of the car insured was a sedan instead of a hatch back, I notifed them about the error and they rectified it. On the same policy document I noticed the 5 years no claims policy bonus, but I did not understand what it meant so i ignored it. I feel that it very unfair of them to reject my claim on those base I was able to notify them of their error.