If you bought it from a local hobby shop, take it back and talk to them. It's not really their fault or problem, but the good shops.....

And no matter what, I'd get on the phone right now to H9. There actually is a better than 50-50 chance they will not want the bad wing panels back, and an excellent chance they'll send a new set that'll get to you in a heartbeat. And while you're waiting....

1/16" really isn't an awful problem. I've seen Sticks put together that badly before, back when there weren't any ARFs, and if the rest of those Sticks had been built better, they probably would have flown ok. And while you're waiting on the new wing..... If I were you, I'd think awhile about how to work up a couple of staggered joiners. It would be a snap for someone with any kind of saw and a small sheet of hobby plywood. You'd really just be turning thin plywood into thicker plywood that's got a stagger in the middle. Measure the thickness of the spar and how far the holes are off. Those measurements will tell you if building a staggered spar will come close to fitting.

And I'd go to your flying field and ask some of the guys there who build how they'd make the two halves match up. If your field is like mine, you'd probably get a couple of guys offer to cut out the pieces for you.

You say you can sand the original spars. If it's easy enough to do, just sand one side. Then shim that side to fit it's hole. Don't get into the habit of filling bad fits with epoxy. It's not a good way to build. And if the wing joint assembly didn't already suggest wrapping the joint in glass, you do want to now. That will make up for any lost strength in the spars at the centerline.

If all of the above sounds out of reach, then you're screwed. And have no other choice but to wait for new wing panels.

I like to always try to work out some real valuable benefit from problems like this. For example, if you don't have a band saw, you really need one to cut out the little plywood pieces. Or maybe turn this problem into an excellent reason to get a belt sander! And a saw!