Claim unfairly declined

It is frustrating and rather unfair to learn that my claim got declined on the basis that no force of entry can be proven, although the phone was ****** from the locker room. I don't know what difference that makes to a phone that was misplaced/ lost - if that is acceptable to the insurer. I insure myself from the risk of losing my phone and the claim get's declined on the basis that I failed to make sure that my lock was locked? This is pathetic.