Hello,
If your refund was not as much as you expected, missing dollar amounts may be caused by a refund offset when an IRS refund is reduced or intercepted to pay off delinquent debt, such as past-due child support, outstanding student loans, or unpaid state income tax. You will get an explanatory letter from the Bureau of the Fiscal Service if your refund is offset. You can also get this information by looking up your refund at the IRS Where's My Refund page.
For more info, click here https://www.irs.gov/taxtopics/tc203 or you can visit the Stimulus hub here: https://turbotax.intuit.com/stimulus-check/
Hope this helps!