I recently dropped my new Sigma Art 1.8 14mm lens (and 5dii) the lens has some pretty bad cosmetic damage and a few small scratches on the front element. But overall would still be useable if I could get the focus to work (auto or manual) since I just want it for landscape. I would greatly appreciate any suggestions on how I can get it going. Currently there are some clunking sounds and something whirring when i try AF and the focusing ring just spins as normal without changing anything in MF. I have attempted to take it apart but couldn't even get the first piece off due to a data cable/ribbon attached to it that I couldn't remove. Any suggestions how to fix the AF/MF?? 

P.S. repair shop have already said this lens is a write off...unfortunately they gave absolutely no reasoning or parts/labour in the paperwork