I didn’t receive stimulus for my dependant

The IRS is required to mail a written notice to taxpayers no later than 15 days after distributing an Economic Impact Payment. This notice to the taxpayer will indicate the payment amount, whether the payment was mailed or direct deposited, and a phone number to call if the taxpayer did not receive the payment. The payment should be received before any communication from the IRS is received by mail.

If you did not get the stimulus payment of $500 for your dependent under 17, you'll get it when you file your 2020 tax return next year.

by the way, your dependent has to be under 17 on 12/31/2020 to get the payment.  The 2019 payments are an advance and the IRS uses birth dates to see if a dependent will be over 17 in 2020.