Any chance you checked your email? Opening another tab is considered abandonment to keep the bad guys from checking how they're doing. Otherwise, I got nothing; Anyone else?
Help - lost game by Abandonment when I didn't abandon

I may have checked my email. I am always busy with other things, when I play. Can you give me my points back, and I'll make sure not to check email. As you can see from my history, I'm progressing very slowly. I certainly am not seeking outside help. Would appreciate getting these points back.

Afraid your points are gone; sorry. You'll get them back though and a dozen games from now, you probably won't even remember this.

A while ago people got 150 free points. But most of them lost it all fast. This is proof that getting point refunds is pointless. Just keep playing. You’ll get your points back if your chess level is true. Look at me after several up down up down I’m back to 1500 hyperbullet rating again. To remain eternally happy, I have wisely decided to retire in hyperbullet.🏖

Is there any way to give them back, or is this just an administrative decision?
You could contact support, but they most likely won't add them back. As said, within a few games you'll be within a few points of where you would have been without the abandonment.
https://support.chess.com/article/346-contact-us
Can I get credit for lost points? About twenty moves into my 20 minute Rapid game, I tried to move a pawn, but the game suddenly informed me that I had abandoned the game? What? No way, no how. To make matters worse, I had waited only about 20 seconds before trying to move the pawn. Here is the link to this particular game, https://www.chess.com/game/live/14944655839