Welcome to Bladeforums mobrien1.
If it's one of the two kick springs that broke, the springs that fire/open the blade (there are two identical springs placed side-by-side), you can purchase replacement springs and install them yourself (I believe there are youtube videos on how to do this, it looks pretty easy).
I don't know where you are located, but in Europe springs can be purchased from the vendor site owned and operated by the Campolins (knifeshop.com), or, if you are in the US I would suggest going to pvk.com, I just checked and they currently have Zero springs in stock (do a search there for "zero" and you'll see them). There may be other vendors in the US that sell them as well.
Just be sure that you get the ones for the Zero and not the Zero+, because they use different springs. It looks like PVK only has the Zero springs (not the Zero+).
Also, it is my understanding that the Zero uses springs that are identical to the ones used in Mikov switchblades. So you might also find springs advertised for Mikov's that will work in your knife.
Good luck.