Same Thing Happened to ME
The EXACT same thing happened to me in the first week I had my 15-22. I had an out of battery discharge (old ammo), and it blew out my extractor, and I didn't notice. A short time later, I lost the extractor spring and plunger, only I didn't notice and kept shooting. So then, the ejection port got messed up because of a few stovepipes that got stuck to the polymer and melted it.
I sent it in to Smith & Wesson, and they replaced the upper receiver, extractor, spring, and plunger. They sent the rifle back perfect working order with a couple of extra mags and a couple of rail sections for the handguard. They also adjusted the ejector.
I got it back in 10 days, and it has run flawlessly for months. I've run more than 5,000 rounds through it suppressed with subsonic ammo, and it is perfect. Just send it in, and S&W will fix it.