They have my like new Monster pack right now for this very reason. I called them after it broke and they sent me a bunch of zipper pulls and instructed me how to change it however after trying without success I decided to send it back to them for repair.
I also have an older Monster with LOTS of use and have never had a single problem with it. Having looked at both packs, I think they're using less expensive zipper pulls now.
Badlands has a great warranty and are great peole to work with all around. You only have the pay shipping to them, they pay for it on the way back.