Rejected gearbox failure claim

On the 10/6/19 I submitted claim with the my insurer who told me to take my vehicle to an Rmi approved workshop in Balfour Mpumalanga. From that time until today the vehicle is in the workshop. The claim department and the workshop were communicating with each other. I had to intervene during the third week when there was no tangible progress between the parties only to find out that the claim department was rejecting the claim. A gentleman by the name of Ashley was having difficulties in approving my claim. I personally called him and explained to him the reason for my car taken for repair but him and his manager seemed to not understand the meaning of broken gear box and they continued disapproved my claim completely, the unfortunate situation my car is still with the RMI not Repaired three weeks down the line. According to Ashley he assumed that is the wear and tear I told him the gear box was broken because it was making unbearable noise. My big question is how can a gearbox failure be classified as wear and tear.