Per the instructor at the last Glock armorer's recertification class I took, Win White Box is infamous for causing malfunctions in Glocks. He said that quality on the WWB has gone down a lot in the recent past and the ammo is really weak. He suggested using Federal American Eagle for practice ammo since it was loaded a little hotter and the QC is much better. I have used Fed American Eagle in my G42 and, I have to say, it has worked flawlessly. I haven't tried WWB in my G42 but have read about a lot of problems with it in .380 and other calibers. I know that we all want our guns to run all ammo, but sometimes it just doesn't work out that way.
I'd give the Fed ammo a try before sending it back. When you call Glock, based on my experience with Brass To Face in my G19, they won't authorize a return until you try something besides WWB anyway. Good luck and I hope you get your gun running properly. I absolutely LOVE my G42 and hate to hear about people having problems with them.
Bub75