Lufthansa failing with their customer service

My bag was damaged during my flight back from Frankfurt in July, i have been contacting their luggage claim department since July and all i have been getting is stories. they have a private company/ contact by the name of Mr Jeff that they use to fix damaged luggage. This Mr Jeff has been giving me stories and clearly my bag will never get fixed nor will i get it back because i have been trying to communicate with this people regarding this bag issue but every time i am told of a new story and this 'Mr Jeff' always makes promises to deliver the bag but then decides not to do so and does not pick up my calls or reply to my messages. I have taken a decision never to fly with Lufthansa again. I am deeply disappointed with their customer service