Additional Claim Referred as Non Accident related By Insurance

6th dec 2020, i was involved in an accident and since the was no sign of any machenical issues i managed to drive 20km to my destination and park the car. i reported a car as non driveable to the insurance when the towing came i tried to drive the car out of the yard but was not able to select gears but the towing managed to tow it from where it was. since i already reported the damaged i called insurance asking about that and i was told if the is any damages that was not reported the assessors will send them as additional claim, my car was towed to the panelbeater on 14th dec 2020 the panelbeater did the quotation and was approved after i realised they did not put the gear/clutch i called insurance and i was told that they just did the 2nd authorization so it seems it was the clutch. sometimes january 2021 i recieved a call from another panelbeater asking when am i bringing the car to them because insurance authorized them to repair it. 19 January 2021my car was towed to that authorized repaired after i done lot of calls to be helped. 16 feb 2021 which is about a month later i recieved a call from the repairer telling me that they cant repair the car because to repair it the car need to drive around the workshop so they cant drive it because of the gear and the insurance did not approve it. i called insurance to find out whats happening and i was told that they dont cover machenical problem and that clutch/gear is a machenical and again its not accident related because if it was damaged by accident i was not gonna be able to drive from the accident so the cant fix it for me i have to do it myself. i never heard and clutch or gear issues while i was driving it before accident and i only drive 20km to my destination and never drove it after that. i need clarity why they dont want to cover that damages and its taking a long time for the car to be fixed