Wow, more kind advice
I realize I've missed a lot here, but I'm not going to address any more of the back & forth nonsense because really, I have more to do with my life than to defend myself against people I've never met, or refute what amounts to completely irrelevant nonsense spewed by a bunch of bullies with too much time on their hands.
HOWEVER, in the event this information helps others who are ACTUALLY LOOKING FOR ADVICE on the issue (assuming those people exist on this board?), here is the outcome: The "advice" here has been mostly FAR off the mark so keep that in mind when asking for "advice." Other than the tip to call an attorney or legal aid for help navigating the paperwork AND to REPLY within 20 days, it was mostly dead wrong.
AND sorry to break it to the all-knowing bullies out there, but in FL they can NOT dip into your child support to repay food stamps so you don't need to worry that your child support payments will no longer go to help support your children should your support order be revised so that you have to pay the DOR instead of your ex directly.
All told, it doesn't look like "reality" is going to smack my ex on the head any time soon. And it looks like me paying the state instead of my ex in no way changes my "reality" either.
AND chances are slim they'll be able to recover costs (as requested) because I am not behind on my child support. So no more worries there.
Hope this information helps someone facing a similar situation. Thanks to all who offered their words of wisdom or support if they didn't have knowledge. If you're faced with this situation, the best advice is: Take a deep breath, call an attorney (or legal aid), draft a response & file it and then wait for the next steps. Either way, you and your family will be fine.