Yep, it happened to a bunch of people including me. I got quite angry at the company making these zippers TBH. But we can’t replace these without redoing the whole case 
(Edit: I mean, on existing units, new ones have a different zipper)
What I personally did was just remove the rest of the plastic from the handle. A metal piece remains, it also has a hole, through which a strip of leather could be mounted, for example, or another handle piece.