A few days, no sweat. A few weeks, ehhhh, ... maybe not ideal. Move things over to the side that's lit or borrow a different ballast or something. (If you have to send the ballast away, that is.)
If it's under warrantee or something then get them to fix it. But if you have to pay shipping, I'd say don't bother, it will be likely more than replacing the switch yourself. If it's not under warrantee you can just replace the switch (or bypass it) .. fairly easily. You can get the switches pretty much anywhere, Home Depot, Rona, Radio Shack, etc. I might even have one kicking around that you could just have, only caveat is I have to find it (eh heh heh
it's in a box around here SOMEwhere ...)