Deductions & credits

I'm having the same issue. My ex and I both filed 2018 and 2019. My ex claimed our son 2018 and I claimed him 2019. I claimed 3 dependents and only got 2200. I wasnt sure if this was because we alternate years. If so our son lives with me 12 months out of the year both years and I pay 50 percent plus of his living expenses. Not sure if I'm missing the 500 dollar credit for him or my other daughter who receives ssi for her father that passed away last year. I'm finding little to no answers for dependents recieving death benefits that qualifies for the stimulus payout.