Send it back they warranty forever. Don't even have to be the first owner.
It’s on my to do list.
My biggest concern is that it started malfunctioning after about 100 rounds. If it was broken out of the box I would mark it down to a problem in manufacturing, the fact it worked for a while makes me concerned about a problem with engineering or materials. If it was put together incorrectly, it is fixable, if it is an engineering or material problem it’s just a matter of time before it happens again. Thus my worry about using it as a primary defense weapon.
I have an old beater Mossberg pump that has been mistreated by myself for the last 30 years and I bought it used. Never a hiccup.