Claim rejected without a valid reason

I am pathetic with the bad service I am receiving from Mtn. I took a contract that came with insurance and I recently lost my phone, when I register a claim it was rejected, because they do not cover ****** or lost phone without any forceable entry.

I have however explained to them that I don't know how it was lost or when it was ******, I only realized later when I got home that my phone is not in my bag. To my surprise no investigation was done to dermine or to reach to their decision to reject my claim. The rejection letter further says that they cover it provided it was ****** at my home or my place of work.... I was not at either any of the two places so why reject my claim and why are they taking so long to give me feedback.

This is a cellphone which I use on daily basis, so how I'm I supposed to go on without a cellphone? Which I'm still paying its insurance at this moment as I type this.