First I would suggest you contact BMW regarding the lack of Warranty service by the dealer.
If that fails you could support one of the vendors here that has a replacement product for sale and is a supporting vendor for the site. You will find him here http://www.lttrunklatch.com/
If that fails you could support one of the vendors here that has a replacement product for sale and is a supporting vendor for the site. You will find him here http://www.lttrunklatch.com/