Poor service from Kohler Motors, Clearemont

I took my BMW X5 to Kohler Motors Claremont , for a noise on my gearbox. They quoted me to repait the noise adn after 8 weeks rep**** to say my gearbox oil pump pin broke. When I enquired abou the way the installaytion was done, their manager Gavin advised that the pin probably broke before I brought the vehcile to them. I contacted a few BMW mechanics and they immediately advise the gearbox was fitted incorrectly hence the pin broke on start up. Kohler motors have declined my claim and blamed it on the pin being faulty before I brought the vehicle to them. Then after I challenged them they then notoified me that they will charge me storage fee per day if I dont ciollect the vehicle.