You should still report the 1099-G.  The IRS receives an electronic version of the same form you did. 

And, look at it this way -- even though you didn't actually receive the refund, your spouse still got the benefit of it, by lowering his back child support.

Also, please see TurboTax FAQ "Do I need to report the state or local refund I got last year? Is it taxable?" below.  It may not count as taxable income, anyway.

https://ttlc.intuit.com/replies/3300438

Thank you John @TurboTaxJohnW15 !

 I definitely will report that I received a joint return 1099-g but the amount i received as an individual,  can i put for 0? Cause technically my ex received the whole amount , and he should report the whole amount on his tax return this year. But since he doesn't make money last year, so he won't need to file tax return even with the 1099-g as income(all his tax related stuff in 2018 will then be just that 1099g state tax return to report). It that gonna be a problem? ( i have the proof of letter from state showing the whole amount is being intercepted)

I read on the forum that the the distribution on joint 1099-g is totally depends on the agreement between the divorced couple. Weather 50/50, or based on income, or in our case, the fact who received it.

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You know, I totally missed your reference to "my return".... in that case, since you're filing a separate return, I agree with with found.  Please accept my apologies!

@TurboTaxJohnW15 Thank you for responding to me! That helps a lot! Is there any extra explanation i need to do for this situation ? I don't want IRS to come back for me after years saying why the amount I put in is different from the 1099G  :persevere:

Not really -- if it's not a large amount (i.e., under $1,000 or so), the IRS wouldn't bother about it.  But if it eases your mind and you're paper-filing your return, it wouldn't hurt to attach a brief letter of explanation to the back of your return.  That can't be done with e-filing though.  Have a great rest of the day!