Tax help for military filers

I want to add, I see in my W-2 for Retirement by DFAS for 2017 and 2018, State Tax was not charged but Federal tax was...as I stated those W-2's were attached to my forms and package and don't make sense why Federal IRS wants $8000 back, as I also had child credit for 8 kids.  This makes no sense and I need answers as I feel the Federal IRS is taking advantage and Turbo Tax software made mistakes.