we got a letter from the IRS stating that we got direct deposit and we got the $2,400 married couple we did not get the $500 per child and we have three children under the age of 18 this letter that I got from the IRS 15 days after their first deposit only let me know about the married couple stimulus and how it was sent to me. How can I get ahold of the IRS and let them know that I did not receive the $500 per child someone told me this letter that I will get so let me know what to do if I did not get the $500 per child this letter does not say nothing to that nature how can I go about getting a hold of the IRS to let them know that they are missing the $500 per child to me
It is not "under the age of 18". It is no older than age 16 at the end of 2020. They had to be born in 2004 or later to qualify.
The IRS phone center is closed but will probably re-open soon.
The IRS FAQ says:
https://www.irs.gov/coronavirus/get-my-payment-frequently-asked-questions
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. If a taxpayer is unsure they’re receiving a legitimate letter, the IRS urges taxpayers to visit IRS.gov first to protect against scam artists.