I claimed 2 children for the last three years. I only received the 1200 plus one 500 payment. I should have received two 500 dollar payments. They are both under 17 yrs

They both are qualifying and I have read every guideline. They lived with me all year, aren't claimed by anyone else etc.

I definitely should have received two payments. Can someone explain this.

Only the IRS can explain 'Why'

https://www.irs.gov/coronavirus/economic-impact-payment-information-center

For security reasons, the IRS plans to mail a letter about the economic impact payment to the taxpayer’s last known address within 15 days after the payment is paid. The letter will provide information on how the payment was made and how to report any failure to receive the payment. 

@DoninGA Nothing on their entire website tells me why I received less than I am entitled to. Thanks